JPRS ID: 8849 TRANSLATION INTRUMENTS AND SYSTEMS FOR MEASURING VIBRAION, NOISE AND SHOCK

• Document Type: CREST
• Collection: JPRS
• Document Number (FOIA) /ESDN (CREST): CIA-RDP82-00850R000200040015-9
• Release Decision: RIF
• Original Classification: U
• Document Page Count: 79
• Document Creation Date: November 1, 2016
• Sequence Number: 15
• Content Type: REPORTS

APPROVE~ FOR RELEASE: 2007/02/08: CIA-R~P82-00850R0002000400'15-9
; , 0R _ ~ u

8 JANURRY 1~80 ~IBRRTION, NOISE AND SHOCK i OF l
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
, .
FOR OFFCCIAL USE ONLY
.
JPRS L~%8849
8~ J~anuary 1~980
Trans~ation ~
I~nstruments and Systems for M~easuring
_ Vibration, ~toise a~nd ~~~hock
FBIS FOREIGN BROADCAST INFORMATION SERVIC~ ~
FOR OFFIC[AL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPR~VED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9
~
NOTE _
JPRS publications contain information primarily from foreign
newspapers, periodicals and books, but also from news agency
transmissions and broadcasts. Materials from foreign-language _
sources are translated; those from English-language sources -
are transcribed or reprinted, with the original phrasing and
other characteristics retained.
= Headlines, editorial reports, and material enclosed in brackets
are supplied by JPFS. Processing indicators such as [Text]
or [Excerpt] in the first line of each item, or following the
last line of a brief, indicate how the original information was
processed. Where no processing indicator is given, the infor- ~
mation was summarized or 2xtracted. -
Unfamiliar names rendered phonetically or transliterated are
enclosed in parentheses. Words or names preceded by a ques-
tion mark and enclosed in parentheses were not clear in the -
original but have been supplied as appropriate in context.
- Other unattrib~~ted parenthetical notes within the bo~y of an
item originate with the source. Times within items are as
given by source. `
�
The contents of this publication in no way represent the poli.-
cies, views or at.titudes of the U.S. Government.
For f:.arther information on report content ~
call (703) 351-2938 (economic); 346~3
(political, sociological, military); 2726
(life sciences); 2725 (physical sciences).
COPYRIGHT LAWS AND REGULATIONS GOVERNING OWi~TERSHIP OF
MATERIALS REPRODUCED HEREIN REQUIRE THAT DISSEMINATION ~ _
OF THIS PUBLICATION BE RESTRICTED FOR OFFICIAL USE OD]LY.
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPR~VED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY _
JPRS L/8849
~ 8 January 1980 -
INSTRUMENTS AND SYSTEMS FOR MEASl1RING VIBRATION, NOISE AND SHOCK
Moscow PRIBORY I SISTEMY DLYA IZMERENIYA VIBRATSII, SHUMA I UDARA
in Russian 197$ signed to press 1 Aug 78 pp 112-117, 143-196,
232-239
Excerpts from book edited by V. V. Klyuyev, "Mashi:~ostroyeniye" ~
~ Publishers, 440 pages, 30,000 copies
CONTENTS PAGE
CHAPiER 11. Balancing Equipment 1
CHAPTER 12. Vibration Test Systems 7
_ .
~ Test Systems Using the Method of Fixed Frequencies......... 8 -
Systems for Product Testing Using the Sweep Frequency
Method 16
Systems With Selectors 26
Systems With Testing Mode Control and Mechanical
Impedance Compensation 29
Polyhannonic Vibration Testing System 29
Systems for Wide Band Random Vibration Testing 34
Amplitude-Frequency Response Equalizers LJith Tunable
,
Filters 35
rlanual Amplitude-Frequency Response Equalizers With
Comb Filters....... 37
Systems for the Narrow Band Random Vibration Testing
of Products 51
Bibliography 65
CHAPTER 13. Systems for Measuring ~nd Analyzing Vibration, Shocks
~ and Noise 66
r
- a - [I - USSR - G FOUO]
FOR OFFICT.AL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
P
F OR OFF IC IAL US E ONLY
PUBLICATION DATA
English ritle � INSTRUMENTS AND SYSTEMS FOR MFASURII3G
� VIBRATION, NOISE AND S~IOCK
- Russian title . PRIBORY I SISTEMY DLYA IZMERENIYA
VIBRATSII,.SHUMA I UDARA , -
Au~hor (s) .
Ed~itor (s) � V. V. Klyuyev
Pul,lishing House � Mashinostroyeniye
- Pl,r~.:~~ of Publication . Moscc:w
Date of Publicatian , 1978
Signed to press , 1 Aug 78
Copies , 30,000
COPYRIGHT , Izdate~'stvo "Mashinostroyeniye", 1978 _
_ - b -
FOR OFFICIAL USE ONLY ~
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
9
- FOR OFFICIAL USE ONLY
~
UDC 621.002.56:534.647+534.3223+531.66(031).
INSTRiJI~NTS AND SYSTEMS FOR MEASURING VIBRATION, NOISE AND SHOCK
- Moscow PRIBORY I SISTEMY DLYA IZMERENIYA VIBRATSII, SHUMA I UDAR.A in Russian
1978 signed to press 1 Aug 78 pp 112-117, i43-196, 232-239
[Excerpts from the book edited by V. V. Klyuyev, doctor of the engineering
sciences, Mashinostroyeniye Publishers, 440 pages, 30,000 copies]
CHAPTER 11. BALANCING EQUIPMENT
- The Main Characteristics of the Balancing Process and Balancing Equipment
[Excerpt] The major cause of vibration in roating mechanism (rotors) is their
lack of balance, which arises during the redistribution of masses about the '
periphery and about the length, something which causes a displacement of the
main center axis of inert33 of the rotor with respect to its axis of ro-
t~~tion. Dependinn on the mutual position of these axes, distinctions are
clr.iwn be~ween static, dynamic and mixed disUalances.
t1 disbalance is termed static if the vibration vectors at both suppor*_s
= are equal. In this case, the center of gravity of the rotor is shifted
from the axis of rota~ion by an amount e. The centrifugal imbalancing force
is P= Mw2e, where M is the mass of the rotor; w is the angular rota- -
tional speed~; e is the displacement of the center of gravity with respect
to the axis of rotation (the.eccentricity).
A disbalance is called dynamic if the vibration veetors are equal in terms
of absolute value and are out of phase. Tf the vibration vectors are not
equal in terms of absolute value and phase, then the disbalance is calTed
mixed.
- 1 -
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
; `
~ -
,
FOR OFFICIAL USF ONLY
In the ma~ority of cases, unbalanced rotors have a mixed
disbalance.
We shall consider the static balancing of a disk, rotating at a speed -
considerably lower than the first critical frequency.
The balancing is.accomplished in the following Isequence. During the
~ initial start of the disk, the vibration vector Ap is n~easured. Then a
test load P.~ is placed on the rotor and durin�; the second run-up, the vector
t1pt. 'Phus, the vibrations are caused by the sum of the centrifugal forces
of ti~c disk and the test load. Then the vibration vector A,~, caused by rhe -
_ tesC ,load, wi11 be A.~ = A01 - Ap. The balancing load is -
P~ - P" ,q o.
'
Its setting angle �6 is determined from ~he vector diagram. Gonse- ~
quently, to achieve balance, instead of the load P.~, it is necessary to
take P6, rotate it through the angle ~g and position it at the same radius.
If the setting radius of the balancing load r6 differs from the setting
' radius of the test load r.~, then P6 can be computed from the from the
~ formula:
P6 - r" A0 p
!'o A~
In the case of static balancing of the given rotor, the balance loads
_ are placed on both sides of the rotor. If their setting radii are equal
for both sides, then the loads are defined by the expressions:
Pi~ r~~ = P~; Pi~ _ .
- If rl ~ r2, then the loads must be corrected in accordance with the
L-ormulas
~ -
Pi;sri = 1'_ai'z: Pi~ + P~,~ = 1~~
ri
- In the case of a dynamic disbalance, the balancing loads are computed
in a similar manner, but Pl~ and P26 are placed on both sides of the rotor.
In the case ot mixed disbalance, tti.e balancing can be accomplished by
dividing the vectors into static and dynamic vectors. It can be seen in
the vector diagram (Figure 3) that the vectors Ao~ and AoA are equal to
half of ~he sum and half o~ the difference of the vihrat~on vectors A01
- and A02: -
. ~o~ = A01 2 '~02 ; A ~oi - Aoz
_ oa= . 2 , �
where Apl is the vibration vector at the first support; A02 is the vibration
vector at the second support.
- 2 -
. FOR OFFICIAL USE ONLY
~
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
_ I
FOR OFFICIAL USF ONLY
'l'lie vector Ao~ determines the static imbalance of the rotor, while A~A
determines the dynamic imbalance. -
In tt~is case, ~he rotor can be balanced by separately eliminating the static
' ,incl clynnmi~ [mbal.3nces in a manner similar t~ the Precedin~ one.
'1'he melhod ot computing the balancing loads by means of complex sensi-
~ tivities has become widespread. This method is most widely employed in
the halancing coupled rotor. systems, i.e., wfiere the number of supports
r~nd hcilancing planes is greater than L-wo.
'I'h~~ iniria:L vibration vectors of a rotor have values of A01 and A02. Prior
_ r~in-up, a test load P~ is placed on the first balance plane of the rotor.
U~~ri.ny; the E-ir.st run-up, the vibration vectors A11 and A12 are measured and _
tlic: f c~.l.lowing coefficients are computed:
;111 - f1~i . �.lt, - An2
uil = ~ , ci:i .
/
wliere ail and a21 are the relative changes in the vibration vectors at the
rotor supports when the test lo~~d P.~1 is mounted cn the first balancing
plane. `
~ 1'rior to the second run-up, the load P.~1 is removed and the load P.~2 is
placed in the second balancing~lane of the rotor. During the second
r.un-u~~, tt~~e vibration vectors A21 and A22 are measured, and the following
coef.iicients are calculated:
A:t -:to~ , A:~ -~oz
u 1 ~ _ - t i,i, 2 = -
p~ , p~~, -
where a12 and a22 are the relative changes in the vibration vectors at' -
the rotor su~ports when the test load is placed in the second balance
~ plane.
The coefficients a are called the complex sensitivities and express
- the change in the vibration vector with a change in the disbalance per
unft weight as well as when it is positioned at the origin for the rcadout
o� the angle of the vectors = 0). These coefficients do not depend on
the test load.
Depending on the angular position, the balancing loads are determined from
- the system of equations: -
1'tii~~ P2ulZ Aoi = C;
1'1i~21 + I'Z~~21 -f- A02 = 0.
In the case of the balancing of a coupled system of rotors with n supports
and planes, the number of complex sensitivities is n2. Tt is necessary to
- make n test runs to determine them,'
- 3 -
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY '
The bal.ancing Loads are found from a system o~ n equations: ~ -
- P~al, + P~i~,i + + P~~�i~~ + Aoi = U~
- P~~~. ~ -t- P~u22 -f- . -F Pnuzn Aaz = 0;
t'~1~~~ ~'�P2pn2 + Pullun Aon , -
Suc11 a system of equations is solved by means of special computer programs
or. usiit~ specialized computers.
The problem is coiaplicated in the case of vibration at frequencies differing
from the rotational frequency~, i.e., in the presen,ce of interference caused ~
; by roller bearings, nonuniformity of the electromagnetic field, etc., as
well as noise transmitted through the foundation an~ from other mechanisms.
- The main function of balancing equipment is the measurement of the para-
- meters of oscillations caused a disbalance in the presence of a high inter-
ference level. ~
The tollowing major parameters of oscillations are measured using balancing
equipment: tfie amplifiude or peak to peak value of a vibrational displace-
ment; the relative phase shift. -
Balancing equipment has filtering units for isolating oscillations which ~
cause a disbalance fron~ the entire spectrum of vibrational frequencies of
the rotating rotors. Additionally, units for.measuring r.he oscillation
, frequency, the spectral analysis of the vibrational speed parameters, the
vibrational acceleration, etc., can be included in the equipment.
Balancing equipment can be composed of instruments intended for vibrational
measurements. By way of example, we shall consider the unit shown in
Figure 1. The rotor being balanced 1 rotates in bearings 2. An induction
vibrational transducer 3 is rigidly secured to the bearing, while the rotor
of the reference generator 9 is rigidly tied to tfie rotor being balanced.
The reference signal generator generates a sinusoidal voltage or pulses,
having a repetition rate equal ~o the rotor frequency.
The, vibrational transducer picks up the bearing oscillat~ions and generates -
a voltage proportional to the vibrational speed of the spectral components.
If the spectrum of the oscillations fa11s in a range in which the absolute
value and phase of tfie transmission factor of the seismic system do not
_ depend on the frequency, tfien the voltage at the output of the vibration`
transducer is:
U(t) = B~ w;ti; cos (w;t + cp;l,
;_o ~
~ where B is the transmission factor; Ai and ~i are the amplitude and phase
of the vibrational displacement of the spectrum component at a frequency
- of w~.
-4-
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
= FOR OFFICIAL USE ONLY
~ Analog integrating 4 is used to convert the signal proportional to the
vibrational speed to a signal which is proportional to tfie vibrational
displacement. Tf it is assumed that the analog integrator is ideal in
a range of frequencies from wp to a.~, then its output voltage is:
B "
U1(t) = f U (r) clc = ~ A; sin (o~;t + cp;), . �
T i=0
where T is the integrator time constant, i.e., the signal level does not
depend on the frequency of the cornponents of the spectrum.
The block of bandpass filters 5 serves to isolate a component Ap with a
frequency of wp equal to the rotational frequency from the spectrum. If
the filter is ideal, if the transfer coefficients at the frequency wp are
equal to unity, and are zero at rotational fre~quencies other than wp, and _
also do not introduce a phase shift at wp, then a single-harmonic signal ~
at the frequency wp is produced at its output:
Uz (i} - B,.4o sin'(cuot + cp,;).
where B is the overall conversion factor (of tfle v~brational rransducer--
integra~or--filter).
The amplitude of the voltage U2(t), which is proportional to the amplitude
of the oscillations AQ, is measured ~rith voltmeter 6; the frequency af the -
oscillations wp is read out on frequencp meter 7, and tfie waveform of the
process is monitored on oscilloscope 10.
Phase meter 8 serves for the measurement of tRe phas~ shift between U2(t)
and th~e voltage picked off from thereference signal generator 9. Sels}ms,
rotating transformers, pulse sensors and other devices whicfi generate sig-
nals, the frequency of which coincides with tfie rotational frequency, can -
serve as the reference signal generator.
f0 6
N
~5! ~ Figure 1. _
3 f yZ
, A block diagram of a standard
. a unit for dynam~c balancing.
, g ~
. ~ Z ~
- In the system considered here, the amplitude and pRase-frequency response
of the seiscnic system of the vibrational transducer, the integrator, the
filters and all of the measurement instruments have l~een idealized. Prac-
tically a11 of the devices introduce considerable errors, especially when
making measurements at Iow frequencies. When des~gn~ng v~Dra~,ional meas--
~ urement equipment, primary attentic~n is devoted to tRP reduction of
- S - .
FOR'OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
of amplitude frequency response errors. Tn balancing ~quipment, the
amplitude and phase freqeuncy rP~ponse errors are of tfie same sign.
The octave and third-octave filters used in vibrational measurements
have an impermissibly wide passband for balancing equipment, while narrow
~ band ~ilters fiave large phase-frequency errors, whicfi are especially marked
in the case of an unstable rotational frequency. Tf the filters are elim-
inated, then small amplitude and phase-frequencp errors are introduced by
the seismic system of the vibrational transducer and the integrator. The
transmission r.oefficients are determined from the formulas:
;2
~~c = - ~
y~c 1- .2,Z + apZ Y= -
2R~
cp~ = arctg
1 - x-
- where v~ is the absolute value of the frequency characteristics; ~ is the
- phasP shift in the seismic system; 2s is the damping factor; x= f~ffP is
_ the relative ~requency; f is the vibration frequency; and fp fs the fre-
quency of the first resonance of the seismic system.
In the lower portion of the measuremer.t frequency range, the errors depend
on x and 2S. The amplitude-frequency error is
x2
s ~(1 - r2) 4p2r'- - 1
and falls off with an increase in S to 0.5-0.55 of the critical attenuation.
With a further increase in S(> 0.55), the error begins to rise, but with
an increase in the damping factor, the phase-�frequency error increases, since
the phase shift is directly proportional to 6. For this reason, in balanc-
ing instruments, the increase in s is limited by the permissible phase-
- frequency errors.
In vibrationa measurement equipment, the rise in the amplitude-frequency
response o� the vibrati:on transducer at low frequencies, in the case oE
inadequate damping in its seismic system, is compensated by means of an
integrating section. In this procedure for reducing the amplitude-frequency
errors, the phase-frequency errors in the lower.portion of the frequency
range likewise increase. For this reason, special vibrational transducers
and inregrators have been designed for balancing equipment.
Analog integrators designed around microelectronic operational amplifiers
have become the_most widespread in contemporary equipment.
- The basic schematics of analog integrators are shown in Figures 2a and b.
The supplemental components Ro~ and Co~ are introduced to limit the direc~
current gains of the operational amplifiers, Y.
- 6 -
FOR OFFICIAL USE GNLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
~
FOR OFFICIAL USE ONLY
Analog integrators frequently peri~orm the function of signal amplifiers,
for signal picked off from the transducer. The schemat~c of an analog
amplifier-integrator is shown in FTgure 2c,
� All III1~310F; integrators have a comparatively slow operating speed. Depending
on the requisite integration precision, the integration time amounts to
tens and hundreds of input s~gnal periods. Moreover, analog integrators
have a limited range on the downside-~(the lower integration frequency
amounts to units, and more rarely, tenths of a Hertz). For this reason,
- when high speed is required ~n balancing instruments (for example, to
measure the vibration in the case a~ transient processes, for mult~ple
_ point instruments), analog-digital, digital and numb~r-pulse ~ntegration
circuits are finding ever ~ncreasing application. Tfie frequency range of
integrators is practically unlimited on the downside, and for this reason,
they can have an integration time equal to one per~od, and in some cases,
even half or one quarter of a period.
- In balancing equipment, the useful signal is segregated from the spectrum
of oscillations by special f ilter devices. Tn the ma~ority of cases, special
electrical filters, as well as multiplier circuits, are used as such devices.
. Balancing equipment can be conditionally broken down into three groups:
l. Equipment with electrical filters;
2. Equipment with selective multipliers;
3. Equipment with combination selective devices.
CHAPTER 12. VIBRATZON TEST SYSTEMS
[Excerpts] Contemporary vibration test systems, the action of which is
based on the utilization of the test methods considered here, take the form
of complex sets, which primarily include subsystems for setting, reproducing,
controlling ana measuring, and analyzing and recording vibration parameters.
The main component of test sqstem~ is the vibrator: the driving element
which is intended for reproducing the specified oscillations. Depending
on the operational principle of the vibrator, various methods are used in
the system to set tl~e test mode. ~lectrodynamic, electrohydraulic and
mechanical vibrators, which were described in Chapter 14, have become the
most widespread in practice. The first two types of vibrators are employed
in vibration sysCems which realize al.l of the modern test procedures. In
this case, electrical signal generators are employed as the setting unit.
Electzvdyn~ntic vibrators make it possible to generate oscillations at higher
frequencies (5-10,000 Hz) than electrohydraulic ones (0-1,000 Hz). Mechan-
ical vibrators are employed in systems intended �or testing using the method
of fixed frequencies.
The major drawback to all types of vibrators is the dependence of their
' transfer funetion on the frequency and load, something which substantially
_
- 7 -
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007/02148: CIA-RDP82-00850R040240040015-9
- FOR OFFICIAL USE ONLY
~ C1 R4
Rx ~~0~ R7
R3
Rx Ree SIf �y2 =
R ~ R C R7 R6 Utu.~
U
U~ y ~eN, y Uau,~ R~ C2 R5 Out -
a) A~ Q) ~j I) C~
. - ~
Figure 2. Basic schematics of analog integrators.
Ro~ � Rfeedback�
complicates the task of reproducing specified vibration paramezers during _
tests in a wide range of frequencies. For tflis reason, to realize any
test procedure, special methods are required to compensate for changes '
in the transfer function w3th changes in rhe frequency and loads.
Systems for Tests Using Harmonic Effects
Tes~ Sz~stems Using the Method of Fixed Frequencie~. A block diagram of
~ vibrational system for performing tests using fixed harmonic vibration
mades and the electrodynamic excitation principle is shoam in Figure 7.
It contains a master oscillator 1, the sinusoidal voltage at a specified
frequency and amplitude from which is fed to power amplifier 2 and the mov- _
ing coil of vibrator 3,.in which the electrical oscillations are converted -
to mechanical ones. Us~.ng masurement t~ansducer 4, matching amplifier S
and secondary instrument�6, the specifi_ed oscillation level is monitored.
When changing from one frequency to another, the 1eve1 of the oscillations
is set by adjusting the voltage of the master oscillator. _
Conventional RC oscillators (more rarely, LC oscillators), operating in a
wide frequency rang~ (5-10,000 Hz and more), are as a rule used as the
master oscillator. The b3sic requirements which are placed on the oscil-
lator are nonlinear distortions of less than 1 percent, a frequency and -
amplitude stability of 3 to 5 percent for 8 hours of continuous operation
and a frequency scale graduation error of 0.02 f+ 1 Hz. These requirements
are the result of the need to reproduce sinusoidal oscillations at specified
frequencies, set in accordance with the test program (primarily at the
resonant frequencies of the product) for an extended length oi~ ~ime.
The power amplif:ier, is a conventional ampliiier, in the final stages of which _
h~gh power vacuum tubes or transistors are used (recently, circuits designed
around tfigratrons have app~ared). The power of the amplifiers used in vi- -
brational test systems, needed to generate the traction forces of the vibrator
. ~ 8 -
FOR OFFICIAL USE ONLY .
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007/02148: CIA-RDP82-00850R040240040015-9
FOR OFFICIAL USE ONLY
ranging from tens to hundreds of tfiousands of Nea~tons, fa11 in a range of
tens of watts to hundreds of kilowatts. The load 4n the amplifiers is
the complex impedance of the moving coil of the vibrator, which as a rule ;
~ is a low impedance and substantially depends on the frequency. ~
- The basic requirements which are placed on modern power amplifiers are:
_ nonlinear distortzons of less than 3-5 percent when delivering the requi-
site power in the working frequency range; the capability of extended
continuous operation tor 8 hours; operational stabil~ty when the load is
dropped; a dynamic range on the order of 60 dB and a low noise level (a
signa7, to noise ratio of > 50 dB).
Electrodynami~ vibrators serve a~ Che actuating element, which generate a
pushing force of up to hundreds of thousands of Newtons with a load lifting -
capability of up to hundreds of kilograms in a frequency range of from units
of hertz to kilohertz and oscillation amplitudes of > 1,000 m/sec2.
; Z 4 5 .
p - ~ s
Figure 7. B1ock diagram for a test system using the method of
fixed frequencies with electrodynamic excitation: '
Key: 1. Master oscillator;
~ 2. Power amplifier; -
3. Vibrator;
4. Vibrational transducer;
5. Matching amplifier;
6. Meter.
Vibration test systems, intended for fixed frequency test procedures, as a
ru1e, are made ~n the form of cabinets. The control and monitor system 3s
housed in one of the cabinets, the individual units of which (for the measre-
~enh oP the vibration parameters, the monitoring of tfie operational modes,
_ the master oscillator, the preamplifier, the power supply of the magneti-
zation coils) are made removable. The power amplifier with the output trans-
former (in high power amplifiers, more than 3,000 VA, the output transformer -
is located outside the cabinet) is housed in another cabinet. The ad~ustement,
monitor and signalling controls are positioned on the front panel. There is
electromechanical interlocking in the doors of the cabinet~.
The technical characteristics of the most widespread madern vibration test
syst�ems wi~h electrodynamic exciters in our country and abroad are listed in
_ Table 1.
In vibration test systems, the action of which ig based on hydraulic exci-
tation of the oscil.lations, tTao methods can be used to generate the spectfied
- 9
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007/02108: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
oscillations: electrical and mechanical. The zneehan~.ca1 me~hod of generating
the set oscillations is tRe simplest. Tt a11ow~ for tRe productfon of only
harmonic osc311ations. As a ru1e, hydraulic pulsators are used as exciters
of the oscillations.
Vibration test systems with fiydraulic pulsators perm~t the generation of
alternating forces of ~ , ~ fa ~n ~
i-~ :~q x~ H H H[_+ W O
~ ~i ,^~i r.: n ~ � ~ ' ~ W C!) .
U . , ~ ~ x : C~ ~ 'r7 'v ~ . ~ .
~ . . d'i~UAW P~+
r-I H . ~ ' 'J+
al
W
rpq~
6
H ~
~ �
- 11 -
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICTAL USE ONLY
~
~ . .
, o N~ ~ o~ i o g t
o a o M e~, ~
,
. . ~ r-r o ; ~ ~ .
~ ~ v c~i ~ -
- rr ~ M ~ G.~. ,r,l Jd ' p� ' ^
V ~ f, S n iJ O N ' �
~ ~ ~ . tt
. ~ ~ ~ o ~ 4~
ri ' ' ~7 I c; i I ~ I
~ :
~i r
GO'
~ ~~n o r_ v, ~ ~ o c~ _
~ ' CI Y1 I~ . C: PI ^ ~1 ~1 ,
A ~
. ~ ' -
- ~ ~ O ~ ~ O ~R~ O O O ~ ~ O f`I O ~ p ~ .
~n r~ O oo rl c~ oc O oo O o0
~ `J~ f~ ~C O ~I-~ ~I t~: V' i~ .P'1 ~O 00 f I 01
~
� R'
yy O O O ~ ~ M ~ O C O ~n O O ,
v rt ~ C C C O ^ PI ^I O N O ~ ~
. ~
~
�~ri ~ i eo ~ i: ~a ~o r oo ~ ^ c o � � ~ ~ ~ ~"x s
~i.7 ri n r,l r'~ ~ r~~i ~O = N G~ ~I v, ~ ~ ~O ~ ao ~D~ ~D ~n C
CJ~i ~ - ~ ~n K o= ^ ~ e�, ~o a~ o~ -a ~o n ~i
f 1 M ~"7 ~/1 I~ � . N t^~ v1 ~D t~ ,
$ S ~ ~ g ~ 8
~ ' CI G1 V1 ~ C '
~ ~ ~ H I Y~ Y~ . r ~ ~
Y~ VI .V1 Vl Vl '
O J .O LL I:. ' O O C ~ 0 C.
O O .-1 ..l CI Cl .C-~ [C^. ^ l'I CI T ~
0
yl f 1 ~l ~
1 i i , Q ~ ~ ~ ~ ~
3
~ ' ~ a ~ ~ F F .O C F F p ~ ~ , � _
F
. ~
: ~ ~ v
~ X C = n p _ ^ r` y ~ ~r. C 1 t
~ ~ = O ~ ~ C C f I v, .C ~C .
v ~ 6. ~1" f. C r rl f~ oC o: Y. O~ C. P. rl
I > I ~ a 'T a' . ~ .
~ ~
~ '
~ ~ .
_ (n. ~ -
q 'rl - ' � " ` .
Q r\ f-I Q C C v~ ~I~ y in ~.r C f i C
C~ ~ C yl r. 1`I v. n
U ~ ~ f i 't ? ~ ~ 'l, Y. 'l, ~.1 I C~ O1 1 f :
5 . �
W '
F-~
~
H
^ 12 -
~ ~
~�f ~ S ~ g ~ ~ .
tJ 0 7 r rl . rl N PI
~ I~ ~ I I i I I I I ~
~,s ~ ~n v~ ~n ~n ~n vi ~n h
' a= ~O O h O Y; O h
M
" v~ ~ O N O O O o O O ' 1~/1 1~/l i~/7 N t~/1 f~/1 t~p
e' L U ~ N f~l t~l N ~ fV (~l
7 ,h I.~ I,
. 1I A W ~ ~ V � ~ V V ~ V V V ~ a7 > > > ~ ,
i~ l �
� ~
1 ~
C' � ~ rr',f . ~ ~ N f~`j v~i ' p O
' r~ - N N N r'1. f~l N f~! ~ fN~.
~ ~ ~ V V ~ V ~ V V > >
~
b
~ �
'
~i ' ' ~ ~y
)
i-' w Y /~`I � . ` ' r~ -rl .~i ~i ' -
O ~ ~ ~ v~ v~ rl ~ O~^~ O ~ O O O O O ~G O ~ -
f? M ~ ~p N N~/1 I`I N 1 N N f 1 ~`I
U �J o 0 0 0 0 0 0 o O r r �1
C7 C7 C7 ~7 C7 C7 ~7 f7 C7 C7 C7 , > > > > > > . >
~
_ W
- a
~
H
- 13 -
~ FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
-
~ o o'o 00 000 00 0 00 00 0 ~no o v, o 00
~ ~i v;C od~i r pc�^ o d o ~ o g c~ K, v o ~ q -
~ f 1 f 1 c~1 C I c~1 O ~7 00 g ~ ~o r 1 n v~ r
' C 1 f I M~'t t~ ~
Y ~
O � �
~
. J 'r ~ ~ � ' ' -
_ ~1 '
~~e ~i f.1 N . ~ -
~ u " ~ ~ p r~ ` ,
v ~ ! ~ ' � ~ - _
~ ti1 ~ ' , _
~ 8 S. 8 8 8 g ~ ~ 8 8 -
, . o . .
v . . . ~ o ~c .
~ ~ ~ ~
5~ a o � o
v 25 gg h'3~~0 0~0 . $ $ g~g~'3~
S .
~ O O V7 O O O O O O O O O C d C C p ~
~ M ~/1 t~'1 V1 M V'1 O PI O vf V'i V1p O C7 C : I
^ N t7 ~O O n N 7 R.
~ ~
v.~s ~~s~'~S~~s~�5.~~~~ ~Ng~~~~~g~
' N f 1 c^. et
l v `
8 ~ $ 8 8 . ~ g
~ ~ ~ N ~ ^ ~g S
~ I ' I~ I I I I I r' ~
~n wn ~n v~ v~ v~ ~n ~ ~ ~ -
. . ~'1 N ~ V1
0 0 ~n o 0 0 0 0 o~n v~ vi g�.,~ $ . > > >
^I f~-~ F~ F!-~ H F~+ F+ F~> F~-~ F:, F- E= H ~ ~ N m
~ C7, vI N V1 t/) Vl v7 v9 H > a ob p
i2
- d~~~ C Q 6~ Q' Q: Q d d< Q Q Q vi rn v: m yri~ -
> > > � > > > < � a Q Q-c -
~ ~ p x 'y^ ~ oN o ~ � _i ? y > /r f,
~ ~ M ~ ~ ~ ~i M N~ ~ N 7 T ~~i
~y ~ {,c~ u cc~ vi w~ c: u ci~
~ j > > r > ~ > > ' Qc C Q i
'd
N
~ _ �
~ ~ �
~ 'x ?f V ~ �
~ v v v v~ v~. ~n ~n v~ ~ vvli vyi ~o ~ n~ -^r,, ~ y> vl v~i ~ t~l C,
O O O G O ~ J O G O O C p O O ~7 r1 r~ r,
~ N f~l N N N f 1 ri fl CI ~I CI f t
N~`I r'1 nl fl rl ~n Vl
O r~ r-, r~ r"-L~ ri r. r, r~. r~ c~ r~ ~n ri n r~. ~ :J :iJ :c7 Iil ft1 L:: W CL'
- U tn VJ tn ~i v~ !h tn :A V7 V7 fn V7 N N N ln fA Vl :/f N V1 !n V1 :/1 VI Jf :n
> > > � 'r->. > > > > BO -
~M~~ HNC, K~M (~~0~ ~r(I~ (lal~ rll~ ~
~
. ~ , .
Key: A. ~'requency range, Hz;
B. Frequen~cy measurement error, ~z;
C. Frequency stabi7.~ty, Hz: 1.5 after 1 hr of operat{.on jS'l7'W~3]
D. Sweep frequency rate;
� E. Sweep drive; ~
- 23 -
FOR OFFICIAL USE ONLY -
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
TABLE 2. [Continued]
I "Bruele & Koer" "sp~o:~~, u K~ep~~, 1(:uwst Denmark
1017 IU3? I035 lU?6 IU27 1047 -
'--'-u~? zo-~ooo~ ~-i~~oiiu i-iuuun z-zooooo , s-ioooo ~A~
,
; ~:o,os; �o,s r~~; o,oi,~+o,~s ' o,i; u,us~ ~u-Sf o,i; i;o
i~~��u,i n~ i�;,� i ru � ~.x)
' - - ~ 0.5 ~a 3 a 0.07~- nu /n~ 0.5 sa S~t
~ ~ r:ifiOf4~ ~,OO?,r-HB,~b ~800T61 ~C`
~ ' 1
~ 3, 4, 3,
flpneon pasecp'rr;u~ (0,3-335) � (I,U-10+1 Ilpxeo.q pas- (0,1.-1001
~ eucuiuuii rpaq~~mu 5, fu, ~iun; . eeprtct+ ettewttwN nu~: (p~
' ~tezna], SWeep (o,i-~uo~ xto Sweep (Q~-tooi.
, de,g/'~nin ~~,o~T~~tllll . UKT~\f11H
. Drive ~rive -
i A'ICRilUH4l'C{~IIII' NIIUIIIIIIIiI ~ Mex.uw~ic- 3~ICK I r01111L1{I . ,3nCKTpOHHbIN~ 3ne~~rpouub~i't
E*ternal. 1neclti~nica ~ ~~~~t,~oriic �"cxa~~~twec~�~i E1ec~ron~~~
~ i~,s i?,5 io� , z,o~ to~ to� ~F)
; �i,o �o,: �o,s; �i,o �o,? �o.t -
. : cf.~tion nu u.i~iocro ~�u), as--i.o u,s . _ _ ~
Hz Hz ~
+ 4$ $i 6U � 8U � )0 3U ~ ~ ' ~ -
.
j ~.n ,t.s i.; t,o 0 0 ~ J~
_ ' z; 10; 30; lU: IUI); 300: 10; 30: 100: I.U: 3.0: I(1; 30; ?A: 10.; 30; 10} ?0: I(10;
; iou i~,ou ~~u; ioou; iuo;.?ao; iouu iuo; ;ou; iooo 300; iooc
30UU
~ .
u 10 . ~r.~
~ , ,
~ 4UD ' i~11 i 4i i 25 > 15 -
i
jKey to Table, 2, continued]:
F. Generator output voltage, volts;
- G. Nonuniformity 3n the amplitude-~requency response, Uout, d8;
- H. KNI, % [not further defined];
I. Dynamic control range, dB;
~ 24 ~
F~R OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
' -
TABLE 2. [Continued]:
~ VSS' . ccc~ . ~n~;~,and n~~~:~~~H ~
n~p~�o ~f ~ I
~ 9 9 ~ 9 Z ~
~ i
~ f,y-L~f Uonf ~ ~Ont ~X~-~~f u0na .
~ I
~ f2 � ~
~ /4 '
~ ~
rv 1J (
f uon!
1S 16 1B J9 - 21 - 23--24--25~
D D � D. i zo z~ p ~ p
. ~
I ~o~[-zz Z~--24---23 ~
I ti
~ zo Z~ D D
Figure 17. Block diagram of a closed multichannel system for poly-
harmonic vibration testing.
Key: 1,2. Heterodyne oscillators; 3. Cry~tal heterodyne oscillator;
4. Units digit mixers; 5. Bandpass filters; 6. Tens digit mixers;
7. Bandpass filters for the tens digit; 8. Switches; 9. Mixers;
10. Bandpass filters; 11. Ad~ustable gain amplifiers; 12. Adder;
13. Common mixer; 14. Low pass filter; 15. Preamplifier;
16. Power amplifier; 17. Vibrator; 18. Vibration transducer;
19. 'Matching amplifier; 20. Emitter followers; 21. Synchronous
detecrors; 22,24. Amplifiers; 23. Selective crystal filters;
25. Rectifiers with filter.
Fol].owing the bandpass filters 10, the signals of each channel are fed
through the variable gain amplifier 11 to the adder 12. To shift the
complex signal spectrum into the 1ow frequency range, the composite signal
' - 33 -
FOR OFFICIAL USE ONLY .
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
and the crystal heterodyne oscillator signal are mixed in the common mixer
13. Low pass filter 14 passes the difference frequencp signal. Thus, we
obtain an output voltage wfi~ch contains the requisite harmonic component,
the number of which is determined b}* tRe munber of generator channels and
the requisite nature of the force excitation. This signal is f.ed through
preamplifier ].5 and power amplifier 16 to vibrator 17. Ttie reference
signals, Uon i, for the block of analyzers are picked off from the bandpass
filters 10 from each channel.
The i-th channel analyzer consists of the following series connected sections:
matching amplifier 19; emitter follower 20; synchronous detector 21, which
operates in the frequency mixing mode; voltage amplifier 22; selective ~
crystal filter 23; amplifier 24 and the rectifier with a filter 25, the signal
from which is fed to the variable gain amplifier 11.
A distinctive feature of this system is the capability of obtaining a large
number of discrete harmonics with a variable gain for each one, something
which permits the simulation of a random process with a specified spectral
density in the requisite frequency range, Tn this case, the test conditions
approach operational conditions.
A feature of the circuit design of the system is the multichannel nature
- and closed aspect of the system, which permit the stabilization of the
1eve1. of each harmonic. The precision in tfie operation of the system in
the case of high open loop gain is basically determined by the errors in
the feedback circuit.
Systems for Random Vibration Testing
Systems for wide band random vibration testing. The transfer function of
~ the vibrator--product mechanical system changes with a change in the
- vibration frequency and the product properties. The results of Eull-scale
product tests are shown in Figure 18. It can be seen that are three sharp
resonances o~ the structure of the product being tested at frequencies of
740, 1,200 and 1,600 Hz on the curve (Figure 18a) for the ratio of the
acceleration to the input voltage, u, as a function of the frequency, besides
the resonance at the center frequency of about 120 Hz and the high fre-
_ quency resonance ],200 Hz), due to the properties of the vibrator. Shown
in Figure 18b is a curve in wfiich the vibrator resonances have been corrected,
in which case, the natural resonances of the structure of the product being
tested have not been eliminated. Shown in Figure 18c is a curve which illu-
strates the total e~uilization of the resonances of the vibrator and the
structure being tested.
To compensate for the nonuniformity of the amplitude-frequency response of
the vibrator, equalizing devices are needed, the frequency characteristic of
- which is the inverse of the frequency characteristic of the vibrator with
the product mounted on its table. To compensate for the resonances of the
vibrator--product system, si`milar correcting devices are needed having a
-34-
FOR OFFTCIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
frequency characteristic which is the inverse of the frequency character-
' istic of fihe vibrator--product syste~m. For this reason, in vibration
test systems, for the purpose of compensaCing for the resonances (peaks)
and antireson.ances (valleys), special devices, equalizers, are introduced
into addition to the devices whicR specify, reproduce and analyze the test
mode. Two systems for generating a spectrum of wideband r~andom vibrations
are employed as such equalizers: systems with selective tunable filters,
which can be tuned to the pea~s and valleys in the frequency response of
the vibrator--product mechanical system; and systems wifih cotnb filters,
which can have eitfier manual or autcrmatic control of the amplitude-frequency
response of the vibrator-~-product system.
~ ~ ~
3 dB
~
" �~~8~~$~~ ~ ~g~~~~~ ~5~~g~~~~
(~A~ a) 6J (C) e)
Figure 18. The amplitude-frequency response curves of the vibrator--
product syatem:
Key; a. Without compensation for the resonances;
b. With compensation for the vibrafior resonances;
_ c. With compensat~on for *_he vibrator and product resonances.
~ " s
z fJ 4 p a
~
e
Figure 19. Block diagram of a system for wide band random vibration
testing with tunable filters.
Key: 1. Noise generator; 2. Programmer for the acceleration spectral
density; 3. Equalizer; 4. Excitation level regulator; 5. Power
amplifier; 6. Vibrator with the product; 7. Vibration trans-
- ducer; 8. Spectrum analyzer.
Amp Zi~ude-frequencr~ response equaZizers with tunabZe fiZters. Sfiown in
Figure 19 is a block diagram of a system with tunable filters. Each of
the compensators of tRe equalizer 3 in such systems take the form of a
device which contain tunable filters with a variable Q and analog com-
puter components, wfiich realize inverse mathematical functions. The filters
make it possible to produce peaks and valleys in the frequency response.
By tuning them to the peaks and valleys in the frequency response of the
-35-
_ FOR OFFICIAI. USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000240040015-9
FOR OFFICIAL USE ONLY
mechanical system, recorded manually or by means of a recorder, and intro- -
ducing a definite attenuation in eacR filter, one can achieve camplete
equalization of the frequency response of the vibrator--product system. This
equalization procedure is accomglished prior to testing, for which a low.level
sinusoidal signal 0.1 of the specified level) is fed to the input of the
equalizer, so as not damage the product. A signal of the specified spectral
- deAsity ~n the requisite frequency range is fed to the input of the equa:'�.~zer
from noise generator 1 through the programmer for the acceleration spectral
density 2, or it is supplied from the output of a tape recorder on which the _
actual vibration process is recorded.
- ~
~
� j~
~ ~~li Figure 20. Scheme for the generation of the
~ ~ acceleration spectral density by
~ 1 means of comb filters.
~ ~ I l
11 Key: 1, 2, n. The amplitude-frequency
~ / ~ ~ ~ ~ ~ response of the filters;
0 f
Curve A is the level of the spectral
density.
2 3 '
~ ~ II
~ Z 3 4 5 7 _
rw ~ - J'J � D 6
I. ~ I
~ z 3 ~
j e
Figure 21. Block diagram of a system for wideband random vibration
testing with comb filters (manual control). -
Key: 1. Noise generator; 2. Filters; 3. Level controller;
4. Adder; S. Power amplifier; 6. Vibrator; 7. Vibration
transducer; 8. Para11e1 analyzer.
Such a method of equalizing the frequency response is effective, and using
it, one can obtain bet~er equalization (with an accuracy of + 3 dB). How-
ever, it has not found widespread application because of substantial draw-
backs. These included the necessity of recording the amplitude-frequency
_ response of the sy~stem prior to making the tests; the complexity of the
a7.ignment, especsall}r in the presence of a considerable number of reso-
nances; the impossiB~lity of generating the spectrum of a random vibration
process which di~fers from a flat one; and ~he necessity of retuning the "
= equalizer when the resonances of the ob~act change during the resting
process.
-36- -
FOR OFFICIAL USE ONLY _
~ S';
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007/02148: CIA-RDP82-00850R040240040015-9
FOR OFFICIAL USE ONLY
Manua2 cnnpZi~ude--frequency response equaZizers wi~h comb fiZ~ers. Tt is
conven~ent to equal~ze tRe frequency~ cP?arac~er~st~c of the mechanical
system of the vibrator~-product and generate the specified spectral acceler-
ation density by means of breaking the spectrum of the input signal down
into a large number of narrow frequency bands by means of a set of narrow
band Eilters, connected in parallel, or so-called comb filters.
The possibility of designing a system with comb filters is due to the fact
that when generating the specrral density, a change in the time-wise form _
of the random process may not be taken into account. For this reason, a
certain de~inite mean level of the spectral density in a narrow frequency
band can be spec~fied in each individual protion of the spectrum. However,
for purpose of obtaining a sufficiently precise reproduction of the specified
spectral density, it is essential to strictly observe the uniformity of the
input noise signal, as well as the nattow band response and rectilinear
nature~of the amplitude-frequency response of the filters.
Thus, a narrow band equalizer with comb filters breaks the spectrum of the
- random signal coming from the noise generator down into n ad~acent bands
with a variable attenuation in each band. -
� A spectral density curve (curve A) for fihe acceleration at a specified point -
on a vibration test stand or a product, obtained by means of comb filters
: is shown in Figure 20.
The value of the accelera~ion in a narrow band of frequencies ~f is obtained
by integrating the acceleration spectr._31 densifiy in this passband and is -
monitored by means of an analyr.er having a filter for each band similar to
the filter generating the spectrum; as well as a square-law detector, an
- integrator (averag~ng dev~ce) and a recorder.
A block diagram of a vibration test system with comb filters is shown in
Figure 21.
Noise generator 1 generates a signal which has a uniform spectral density -
in the requisite frequency range. This signal provides excitation in all
of the frequency band simultaneously. Using s spectrum analyzer, the non-
uniformity of the amplitude-frequency response of the vibrator--product
system is determined. By adjusting the output levels of the signal from
the output of the filter~ 2 by means of level controls 3 manually, the
amplitude-frequency response is equalized and tfie specified spectrum is
generated, ~rhich is fed to vibrator 6~rom adder 4 through power amplifier
5. To prov~de for good equallzation and precise generation of the specified
spectral density of tfie random~process, each filter should have as narrow a
passband as poss-Cble (it is limited by the averaging time of the spectral
density measurement channel and the complexity of the filter design) and
as great a control depth as possible with suEficient rectilinearity of the
- amplitude-frequency response. The "MB Electronics" Company (US) recommends
the use of 80 f ilters witfi independent control of the attenuation of each
- 37 -
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPR~VED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9
_ FOR OFFICI~L USE ONLY
filter in the arnount of 45 dB to cover a~requency range of from 0 to 2,000
Hz. In this case, the nonuniformity in the overall-frequency response of
the block of generating and analyzing filters does not exceed 3-3.5 dB. To ~
cover a range of from 10 to 2,~00 Hz, the "Derrotron" Company (England)
recommends that there ~e 48 ~ilters in sucfi a tes~ system and the "Pay-Ling" _
Company (England) offers 27 third-octave filters to cover the range from
20 to 2,000 Hz.
The spectral density level of the random process reproduce by the vibrator -
is monitored by means of a measurement instrument and an analyzer, which
allows for the measurement of the acceleration spectral density throughout
the enCire specified frequency range or at any of the narrow frequency bands,
isolated by means of the analyzing filters, identical to the filters of the
generation unit (the equalizer). As a r.u1e, there is a cathode ray tube
display witfi long persistence at tfie output of the analyzer. Tt makes it
possibl~ to observe the picture of the vibration spectrum when aligning
the system, as we11 as tfie during tfie testing process. By comparing the
resul.tir~g spectral density with the specified one, the precision in the
execurion o~ the program i~ assessed.
An actual vibration recorded on magnetic tape can be reproduced by means of
such systems. Tn this case, a tape recorder is used instead of the noise
generator, and a sinusiodal voltage generator is used to equalize the fre-
quency response or the vibrator.
These systems have found limited applications because of the existing .
deficienctes. Manual equalization of the frequency response and the gener-
ation o~ the specified spectrum in the case of a large number of channels
takes ~.tp a great deal of time and can run up to several hours, in which case,
the ser~~ice life o~ the product being tested is exhausted. Instability in
- the operation of circuit components, especially the noise generator, has an -
influence on the results, since the control system is an open loop type.
The technical characteristics of manual control systems for wideband
vibration are shown in TabTe 3.
The principle of spectrum splitting of the input signal into a series ~f
narrow frequency bands by means of comb filters, ~ust as in the case of
manual control, is utilized in vibration test systems u~ith autamatic eontroZ -
- of zuideband random vibration. However, automatic level control devices
(AGC) in each frequency band are included in the complement of systems with
automatic control.
The block diagram of the SWU-ShSV-2 80-channel automatic:control system
- ~or wideband random vibration which was develi~ped in ihe U~SR is shown in
Figure 22.
A noise signal with a uniform spectral density in a specified frequency
range (from S to 5,000 Hz) is fed from noise generator 1 to the block of
-38-
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPR~VED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIA~. USE ONLY
driving filters 2 and broken down into 80 ad~acent bands. Noise generator
1 has two channels with independent noise sources, and in tfiis case, the
even filters of the equalizer are connected to one channel while the odd _
filters are connected to the other channel of the noise generator to avoid
cxoss,correl,at~o~ of the output signals of two ad~acent filters [it is
- assumed that the amplitude-frequency response of the i-th filter is over-
_ lapped only by the amplitude-frequency response o~ the (i+l) filters].
There are two variable gain amplifiers 3 at the output of driving filters
2. The signal from the outputs of the amplifiers is fed to adder 4 and
through low pass filter S, level attenuators 7 and preamplifier 10 to power
amplifier 11, which drives the electrodynamic vibrator 15. The spectrum of
random vibration which is reproduced by the vibrator is monitored by means
of pizzoelectric measurement transducer 12, mounted on the vibration test
stand or on the product.
. The signal from the output of the measurement transducer is fred through
matching amplifier 13 to meter 14 for the mean square values of the acceler-
ation in the working frequency band and to attenuator 8, which is mechanically
coupled to attenuator 7, inserted in the circuit for generating the specified
spectral density. The presence of such coupl~ng between the attenuators is
dictated by the necessity of maintaining the overall gain of the closed loop
- constant wP~en the attenuation level c}~anges. The signal is fed from the
~ 1eve1 attenua.*_or through amplifier 16 to analyzer filters 17, which are
identical to the equalizer filters. The signals are fed from the output of
each ar~aly~zex filter fiR~ougR multiplier 18 to the feedback amplifiers 19,
where they are detected and fed to monitor unit 20 for the spectral density
- of eacA channel. The AC signal goes from amplifiers 19 through potenCi- _
ometers 21 to the AGC unit 22 of each channel, which controls the gain of
~he device.. The specified acceleration spectral density level is programmed _
in the requisite frequency range by means of multipliers and potentiometers.
The measurement instrument makes it possible for the operator to be sure
that the AGC unit is operating in the active range. A11 of the foriegn
series produced vibration test systems with automatic wideband vibration
control are designed on this principle (Table 4).
The systems differ from each other basically in the frequency coverage,
the number of channels, the ban~',width of the filters and the structural
~ design.
The primary frequency range is the band of frequencies from 10 (in some
systems from 20 Hz) to 2,000 Hz. As a rule, this range is covered by
40 to 80 channels, each of which includes one generating and one analyzing
narrow band filter. With an increase in the number of channels, the band-
width of the filters decreases correspondingly when the same frequency range
is covered. As a ru1e, the bandwidth of a filter does not exceed 75 Hz -
(taking into account the fact that the least width of the resonance curve
of the samples being tested reaches 100 Hz at average frequencies). Tn
some systems, filters with an identical absolute bandwidth are taken as the
basis, where the bandwidth is SO Hz for a 40 channel system, for example,
39
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
TABLE 3
The Teci~nical Characteristics of Manual Control Systems for
Wideband 'Vibration
TYPe, ~A) (B) wu~~u~~ ,q~D~.n~� ~E~ ~
An:ui,r~rni IIO:IOCLI C~c~tcrnu
'frn~ ~inc~o 4l'l'NIIII
~~Alr\111 48CT07, K81IA.70B 'IUC107' tiI1:IL1(1L1 nNAIIJIOI~, YIIU.11178
rll (,III:I6T[)OA. As 11 Ill\1l'~1t111(A
'Cam an ~ u k'ilters
SPV"Z ('f1B�3 ?q-2p00 30 ~ oKr AKTHB{IbIC 30 ~ ,
i
(CCCP) 20-SOUO 36 4~5 ~C~ RC ~nnbrpsi
nocu~i(1>
� ("US~~ Active iiorpaQ~ TNtlB ~
R~ tt-~c
I
r~Pay_Ling ~2)
�Tlaii-JiF~EU~n 20-10000 27 ~ oxr Ilaccnexb~e 45 ~/~�o~cTaett~+e '
- (Atirm~A) 3 QC~. ' LC ~~~nbrpw; oc;uu~- ~
C~g1an ~ ~ ~'~asQ.~.'ve r ~ ~~r~,5~
_ ~
' ME/MA ' '_'6; 39 10, ll, - 60 ~n.abrpw, aNa.vo- ~
- � uJ~I1Hf� 1~~ ` ~II411WC~~II.7LTrN\I ~i
I
� (Atirm~a) 14, 3Q, ~ ebip[IHIIHB:ITt.9A;
50, 100 ' ocw+nnorpa~; ~3~
ME/MA sz 10, ] i,. ~ eonbrn~erp
~~Lingn I ~2, is,;
(England)! ' ia, is, , .
16. 17. .
. 1 R. 25,
30, 50
~9~ f8l 17 1S 1f
d ~ Q 1B Q ~7
20~
. >9~ i8~
d � ~ If
_
ZZ
Figure 23. Block diagram of a syste~. for wideband random vibratim
testing with electromecRan~ca7, ~i7.ters.
Key: 1. Noise generator;
2. Lo~r pass f~ltex;
3. High frequency oscillator (carrier~;
4. Frequency divider;
16. Modulators;
6, 15, 17, 19. Amplifiers;
7. Shaping filters;
- 8. Variable gain amplifiers;
9. Mixer;
10. Demodulator;
11. Low pass filter;
12. Vibr.ational test stand;
13. Vibration transducer;
14. Matching ampl~fier;
18~ Analyzing fi:~,ters;
20. Automatic gain control;
21. Vibration meter;
22. Spectral dens~tp monitor.
Thermocouples, which have a volt-ampere eharacteristi,c close to a parabola,
are used as the squarers. Tn this case, the thermcouple is employed in a
cathode follower circuit configuration to increase tfie input ~trtpeda~ce of
the thermal squarer.
-48-
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
Square-la~ detectors designed around diode-resistor networks which repro-
duce the piecewise-linear approximation of til~ parabolic function have become
the most widespread. WitR a preci~e approxi'matien of tAe paraHola in the
requis3:te dynami:c range (approximately 40 dB), tfie c~rcuit of such a squarer
can be complex and expensive. gor the purpose of simplifying the c~rcuit,
the square of the mean value is measured instead of ttle mean square value
(the detector of tfle mean values is a squarer~. TRe systematic error arising
in all of the filters is identical. For no~se wfith a normal distribution it
is equal to 13 percent and can be taken ~nta account in the scale graduation
of the equipment. ~y an appropriate choice of tfie discharge ~ime constant
Td and the charging time constant T~ of the detector, this error can be
_ reduced to a minimum. For a ratio of Td~T~ = 4~ it is practically absent.
An advantage of this circuit is likewise the fact that the mean value
detector requires less filtering and is less sensitive to a limited random
signal than the square law detector (the low pass filter averaging time
constanr can be chosen several tens of times 1ess~. The signal is fed from
the mean value detector to a mean value indicator, a quasi-square-law detector
and to the AGC circuit. ~
To make precise measurements, it is important to efficiently choose the
parameters of the averaging device, for wh~ch eitRer an integrator or a 1ow
pass filter is used. Tfle precision of an integrator is limited by the true
time of the,measurement, while low pass ~ilter accuracy is also limited by
the low pass filter time constant. A low pass ~ilter yields satisfactory
results when T/T~ > 4, where T is the measureiaent time and Tf is the con-
stant of the low p~ss f~lter. With an ~ncrease in tfie 1ow pass filter time
constant in tfie case of ineasurements of long duration, tRe averaging error
of the low pass filter fa11s off to tRe value of the integration error. A
low pass f ilter is significantly simpler than an integrator. It usually
takes the form of a passive RC network. An integrator is designed around
a direct current amplifier with a Righ negative feedBack level.
Domes*_ic single or multichannel narrow profile meters (M1730, M1635, etc.),
graduated in a2/Hz or a cathode ray tu6e can be used as the recording device
in the monitor units. Tn tfiis case, the signals from the outputs of the
averaging devices are fed to a switcher, w11icR "interrogates" all of. the
detectors successively, and a sequence o~ square arave pulses is formed at
its output. The pulses are amplified; they can be visually observed on
the screen of a cathode ray tube, the sweep of which is syn~hronized with
- the switcher rotation. The position of each pulse on th~ screen corresponds
to a specific filter, while the pulse Reight is proportional to the spectral
density in the given frequency range.
When designing a measurement channel, it i~ essential co take into account
the error which arises because of the unequal ror.Ldth of the passbands of the
analyzing filters. With an increase in tfie width of the passband of a f ilter,
the level of tlie spectral density increases. To reference the spectral
density to a constant Bandwidtfi, voltage dividers are provided in the channels
in accordance with the relationsRip: ~dgn Ofe~st.
-49-
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007/02148: CIA-RDP82-00850R040240040015-9
FOR OFFICIAL USE ONLY
Light signaling is provided in some model~ o~ control. devices for opera~ional
monitoring of the specified spectral density 1eve1.
In moderti control devices, bes~des those instruments which are intended for
monitoring the spectral density in the individual channels, tliere are also
instruments for measuring the mean square acceleration tfiroughout the entire
working band of frequencies. Tn this case, a square-1aw detector is used in
the vibration meter, and the vibration meter is graduated in units of vibra-
tional acceleration.
The operational principle of the AGC unit in random vibration control systems
is similar to the operational principle og the AGC circuits used in vibration
test systems intended for reproducing and controlling sinusoidal vibrations.
However, it is the spectral densit}* level in narrow pas~bands which is regula-
ted in them, and not tfie sinusoidal signal 1eve1. For tfiis reason, besides
the vibration measurement transducer and tfie matching amplifiers, the feedback
circuit should contain the corresponding number of narrow band filters (accord-
ing to tTze number of system cRannels), amplifiers, detectors and low pass
filters. The components o~ the analysis circuit are usually employed as
these elements. _
The basic control section is the variable gain stage, where K= K(Uy), where
the signal from the output of the narrow band filter
y (t) = A (t) cos [wot + ~p (t)],
is Eecl to its input, wfiere wQ = 2~rfo is the center frequency of the filter;
A(t) and ~(t) are slowly changing functions of time; A(t? is the signal envel-
ope expressed as a Gaussian distribution funetion and has a frequency spectrum
f.rom zero to ~f/2.
During regulation, the amplitude A(t) should change without changing the dis-
- tribution function. However, depending on the time constant of the RC low
pass filter of the AGC detector, the law governing the distribution of .4(t) -
can change. The actual and the statistical characterist3:cs of the variable
gain output stage should obviously not differ during regulation, if tne time
constant of the regulation circuit is large. However, at large values of the
regulation time constant, tAe equalizer responds exce~sivelp slowly to a change
in the signal at the vibration test stand.
The lower time limit ~or system response is determined by~ tfie stability con--
ditions, to assure which it is neces~ary tfiat at any point in time the fo1-
lowing condition be met:
H
nOJRC ~ 1'
where H is the transfer function of the channel from the output of the shaping
filter to the outpu~ o~ the AGC detector; ~f is the passband of the analyzing
filter.
-50- ~
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007/02148: CIA-RDP82-00850R040240040015-9
FOR OFFICIAL USE ONLY .
An AGC circuit is usually designed so that ~Q~RC = 24 - 100. Tn this case,
the probability density of the amplitudes of the output signal of each'chan-
nel of the equalizer practically does not differ from the Gauss~an distribu-
- tion. Tf a vacuum Cube or semiconductor device is u~ed as the cantrolled ' -
AGC element, Chen wi~h high level regulation, distortion of the distribution
of the instantaneous values of the amplitudes of the noise signal being re-
produced can occur. For this reason, it is necessary to use those AGC devices
in which the attenuation factor of the voltage divider or. attenuator is auto-
matically regulated, rather than the current of the active device (the vacuum
tube or transistor). The AGC unit is simplified, and there is no electrical
_ coupling between the circuits of tF~e equalizing device and the AGC unit. Such
a circuit has been used, for example, in the domesti~ StJVIJ-SIiSV-2 system, in
which a voltage divider consisting of a resistor and a photare.~istor, illumi-
nated by an i.ncandescent 1amp, is used as the AGC device.
A specific feature of the .A.GC device with tfie photoresistor is the linear
response of its volt-ampere cnaracteristic, since the resistance does not
- depend on the applied voltage, and such a device does rl~t introduce nonlinear
distortions. The brightness of the incandescent lamp wh~.ch ligh.*_s the photo-
r.esistor changes in accordance with fihe cRange in the conerolling voltage _
acting at the input to the AGC dev~ce.
Systems for the narror~ band random vibration testing of products. Vibration
test systems intended for reproducing a wideband random vibration make it , ;
possible to simulate mechanical effects closest to real effects. The control
equipment for such systems is complex and expensive, and for this reason, it
is used in large test centers. Under plant conditions, equipment is used -
which basically makes it possible to simulate wideband random vibration.
Vibration test systems which test products using narrow~band random vi6ration -
with frequency scanning of the signal, are emplayed for this purpose. These
systems are usually built on the same principle as systems for testing with
the sweep frequenc}r method. However, instead oJ~ a sine wave sc~eep frequency
generator, a special narroar hand noise generator is used with scanning of the
center frequency, and a functional unit wfiicfi amt~l~fies the noise signal
level by 3 dB/oct depending on the frequency is additionally introduced into
the AGC system. 6.
Because of the similarity in the operational principles of the automatic .
control for sinusoidal and narrow band random vibration, tfiey can struc~-
turally be combined in a single instrument. The domestically produced
SUW-USV control system and the 1026 and. 1027 control generators of the
"Bruele and Koer" Company are designed in this fashion.
Shown in Figure 24 is a block diagram of a system for testing products with _
narrow band random vibration having a SUW -USV type control generator. The
- system operates as follows. A random signal with a normal amplitude distri-
bution and uniform spectral desn~ty is fed from wideband noi:se generator 1
to narrow band filter Z having passbands of 3, Y0, 30, and 100 Hz at a fre-
quency of 10 KHz by means of balanced modulator 3 and high frequency sine
_ wave signal generator 4(40 KHz), the narrow band noise is converted to the
~ 51 -
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
z s ~ ~t ~ =
~ 3 ~ � ~ ~ .
1 4 6 9 1d
ti . - ~ v
/v N
7
~ Q r r4
_ 16 1f
� 97 a
Figure 24. B1ock diagram of a system for narrow band random vibration _
test3ng,
Key: l. Wideband ra:idom noise generator;
2. Narrow band filter;
3. Balanced modulator; -
4. High frequency sine wave generator at a~ixed frequency;
5. Variable gain ampl~fier;
- 6. AGC rectifier;
~ 7. AGC amplifier;
8. Mixer;
- 9, 10. Variable frequency sine wave generator;
11. Low pass filt~r_;
12. SUW-3 output amplifier;
~ 13. Power arnplifier;
= 14. Vibrator;
15. Vibration transducer;
1.6. Matching amplifier;
17. Vibration parameter meter.
range of higher frequencies (50 KHz). The signal is fed from the output of
_ the balanced modulator to the tuned var~ab~e gain amplifier S, the center
frequency of the filter of which is tuned to the upper sideband of the signal
from the balanced modulator. To generate the 1ow frequency signal in a spec-
ified frequency band, mixer 8 is used, to which narrow band noise is fed from
the tuned amplifier and the sinusoidal signal from the 50 - 60 KHz variable
frequency oscillator (9, l~). The output signal from the mixer is fed to low
pass filter 11, where the signal witfi tlie difference frequency is isolated.
The narrow band noise derived in this manner is fed to the output amplifier
of generator 12 and to power ampli.~ier 13, which drives electrvdynamic vibra-
tor 14. The mechanical oscillations are converted by~ vibration transducer 15
and fed through matching amplifier 16 to the vibration parameter 17 and to the
input of the AGC block 7. -
The dynamic working range of the AGC device is 50 dB. Similar control gener-
- ators of the "Bruele and Koer" Company, the 1026 and the 1027, have a dynamic _
-52-
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
. ,
FOR OFFICIAL USE ONLY
- control range of 80 - 90 dB. Tfie frequency sw~eep is a+~ccnnpl~sRed automat-
ically by means of.an electric motor. The SUW-USV generator operates in
- a frequency range of 5~ 10,0~0 Hz.
Systems for Mixed Vibration Testing.
There are no specially designed systems for tfie reproduction of mixed
vibration. The systems used at the present time are combination ones, which
" include the control equipment for harmonic and random vihration. Two conduct
the tests using the method of sinusoidal sweep frequency w~th a wideband
signal superimposed on it having a specified spectral denstty, the "Bruele
and Koer" Company recommends putting equipment together in the configuration
shown in Figure 25. The sinusoidal excitation signal is generated by the y-
type 1047 controlling generator 4, w~ile the randcrQ s3gnal is generated by
means of a type 3380 automatic equalizer-analyzer 1,2. Tfie distinctive -
feature of such a circuit is the presence of the type 2021 heterodyne track-
ing filter 5 in the feedback circuit, where the sinusoidal signal at the
output of the filter is utilized to control the s~nusoidal excitation level.
The random signal is fed tfirough a bandstop filter, ~ncluded in the comple-
_ ment of the 2021 instrument, to tRe compressor input of tRe eq~alizer-
analyzer to control tfie spectral densitp level.
Multichannel Vibration Test Systems
The behavior of a structure when acted upon by vibration depends on the
external conditions (for example, the exc~ting forces, tfieir point of appli-
cation and frequency) and on tfie inheren~ parameters of the structure (weight,
stiffness, damping, etc.). The determination of tRe response of a mechanical
structure to the application of a specified external force is the primary
_ task of the dynamic analysis of the structure. -
By analyzing the reactions of a simple structure to pulsed or noise exci
tation, its parameters can be determined in a short time and with sufficient
- precision. Analysis of the effect of a harmonic force yields good results.
The analysis of a complex structure by means of a single vibrator used to -
excite the harmonic force is possible in tRose cases wRere the natural reso-
nant frequencies are spaced significantly far apart, while the deformation
- of the structure is of a single type. ~
If the deformation is not of a single type and the structure has rather
scattered frequencies and a neglectably small relationship between the
deformations, one vibrator does not assure reliable results. The analysis
- is considerably complicated if the structure fias natural resonant frequencies
close together and (or) closely related deforma~ions.
In such cases, the mechanical multistage system is reduced to a single stage
one by means of r:noosing that vector of the generalized excitation forces
- for wfiich the trajectory of motion of the points of the structure have a
sinusoidal character (a pure tone~. Using additional exc~tation forces, all
-53-
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
~ FOR OFFICIAL USE ONLY
~ 3 ~ e
N D B D
.4 5 .
2 ~
Figure 25. B1ock diagram of a s}rstem for mi~ced v~.bration effect
testing.
Key: 1. Type 1406 control generator;
2. Equalizer-analyzer;
3. Power amplifier;
4. Type 1047 generator;
S. Type 2021 tracking filter;
6. Vibrator;
7. Vibration transducer;
8. Matcliing amplifier.
1 4
P Z 3 D 3
y 6
1 D 5
Figure 26. Block diagram of a dual channel vibration test
system. '
Key: 1. Generator;
2. Attenuator;
3. Tnverter;
4. Power amplifier;
5. Vibrator; _
6. The product.
of the interfering oscillations are excluded, and the natural resonance fre-
quency, the damping and the generalized Tnass (or stiffnes~) are determined for
this tone. One of the criteria for the correct choice of the vector of the
generalized forces is the absence of phase shifts between the excitation and
the oscillation velocity o~ the individual points of the structure.
Because of the necessity of controlling additional vifirators to excite the
additional ~orces, a multichannel system is required. It is apparent that
a system containing several viBrators of ~he same type, driven by one or
several source operating in para11e1 and controlled Tiy~ one generator, must be
treated as a multichannel system in terms o~ tAe equipment used, since it is
reduced relatively simply to a system w~th one vibrator.
- - 54 ~
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
p4 s
1 Z '3
4 _
3 D S -
~ e
i D f
4
, p s
- Figure 27. Block diagram of a multichannel vibration
test system.
Key: 1. Two-phase generator; _
2. Common level and phase control unit;
3. Units for controlling the level and phase of the
vibrations of each vibrafior;
4. Power amplifier;
_ 5. Vibrators;
6. The product.
Thus, not only the number o~ vibrators in a m~altichannel system serve~ as
the criterion for the system, but also the presence of 1eve1 and phase
control for the excited force of eacTi vibrator.
Multichannel systems are employed in the vibration testing of large
structures, in studying the natural forms of the oscillations of a struc-
ture and to obtain multicomponent vibration.
The simplest multichannel system is a dual channel system, both vibrators
of which excite forces wfiich are either ~n-pha'se or oubof-phase (Figure 26). -
In multichannel systems, it is necessary to control not only the amplitude,
but also the phase of the vibrations of each exciter for the purpose of
producing in-pfiase oscillations o~ the excited structural points of the
- product� being tested. For this, various types of phase shifters are in-
corporated in each channel system.
The block diagram of a multicfiannel sytem for studying complex mechanical.
structurs is shown in Figure 27. The number of channels of this system
is determined by the number of vibrators needed to study the structure of
the product being tesfied. -
An integral part of a multi~hannel system is the generators and control
devices for the level and phase of the oscillat~ons o~ each vibraCor. These
devices can be structurally designed as independent units or as component
parts of other blocks og the system.
-55-
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
The level contr.ols usually take tfie for.m of either attenuators (controlled
or manual), or variable gain amplif iers. .
The phase s~:ifters provide for a continuous phase change by + 180� through-
out the entire frequency range. Tn the case where pfiase shifters are
employed in multicfiannel vibration..teet systems, a ge^~erator is required
which has a two-phase or four-phase output voltage. Phase inverter and
integrator generators most completely meet these conditions. Synthesizers,
which make it possible to provide for computer control, have recently become
increasingly widespread.
The presence of several vibrators and the complexity of the structures being _
tested determine the mult~channel nature of t:he equipment for the measurement
and recording of the vibrations. As a ru1e~ several hundreds of transducers
can be mounted on a complex structure, and ~or tRis reason, the measurement
and recording equipment contains various lcinds of switcfiers. A computer can
play the part of the switcher. To set tfie level and phases at all exci-
tation points, devices are used to simultaneously observe the oscillations
at all of these points.
The procedure for tfie automated control of a specified testing mode is
substantially complicated, since it is necessary to track the amplitude
and phase of the vibration. Tn such systems, tfie amplitude and phase of
t}ie oscillations of each vibrator are controlled by means of ineasuring the
in-phase and quadrature components of the oscillat~on vector, the i~forma-
- tion on which is rooted to the automatic level and phase control circuitry.
The in-phase component is us~ally regulated hy the A~C circuit described
earlier. The quadrature component is employed for automatic phase tuning,
i.e., to synchronize the oscillations of the vibrators. For this purpose, -
foriegn companies have developed and are producing special devices: vibra- _
tion synchronizers, which take the form of automatically controlled phase _
stiifters, which assure the phase agreement of a11 exc~ters in the working
_ range of frequencies. For example, the "Chinken KOF' Company (Japan) is
_ producing a synchronizer, by means of which the vibrations of four vibra-
tors can be brought into phase. Tfie control oscillators (the 1026 and 1047,
etc.~ o~ rRe "Bruele and Koer" Company can also be used in multichannel .
vibration systems. A provision is made in them for the capability of
ad~usting the phase by 360�. Tn the case of the parallel insertion of
several generators of this type in a"master-slave" circuit configuration,
one can automatica7.2y regulate the amplitude of the oscillations of each
vibrator w3th a multicRanne7. system.
Sometimes, for example, in the case of resonance oscillations or strong
couplings between the points whe;ce overloads act, even 3:n the case of good
synchronization, the influence of ad~acent vibrators can lead to system
ins~ability and its failure. At frequencies aBove 200-40Q ~iz, it is im-
possible to establish the parameter of a specified testing mode in the
case of sinusoidal ~nd random viDrations, and to independently regulate
each vibrator of a multicRannel system. The causes of this situation are
the cross~talk coup7.ings and mutual influence of the various excifiation
-56-
FOR OFFICIAL USE ONLY
i
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
points o~ the structure. Because o~ the crosstalit coupl.ing, the overall
level of the oscillations at ~Iie ~oint being monitored can reacR auch a
value that reducing tfie input excitation leve'1 to it has almost no influence
on the overall amplitude of the vifirat3on. 'Var~ous methods are employed to
reduce tRe influence of cross~tallt. For example, to compensate for cross-
talk energy one can use a crossed feed of the vibrators (Figure 28). This
produces exciter oscillations out of pfiase witfi the oscillations resulting
from mechanical cross-ta1k. The cross-talk faetor is:
cF;; = y~ (e~ = U = aU~
, J
where Vi and V~ are the responses at the i-th and ~-th monitor points; ai~
is the mechanical transfer function of the crosstalk to the i~th vibrator
from the ~-th vibrator.
~ Figure 28. Block diagram of a dual
J channel vibration test
_ _ sy~stem witA compensation
~ D -j j j for crosstalk energy.
2 ~ ~ Z a_~ Ke 1. Power am lifiers�
L- , Y~ P ~
4 e; et 2. Vibrator; 3. The product;
~ K,ter Xz~ xt,e, 4 4. Adder: ei is the electrical
~ signal of the i-th vibrator;
e' ~s K i is the electrical transfer
e, K'L ec function o� the additional
- crosstalk supply unit; e~ is
the composite signal of the
i-th vibrator.
9 y 9 y .
~a
_ 3 ~ ~
la
o T x 0 2 x x o x 1a 0 2 X -
1
al a) b) dJ B~ c~ t) d~
rigure 29. Diagrams which illustrate the manner of compensation
for the crosstalk energy.
- The primary task of the crossed feed is to reduce the crosstalk factor cFi~
to a value of less than unity, since in this case, the automatic control
system operates stably and effectively.
Prior to testing the structure, the crosstalk factors at the control points
in the working frequency range are determined beforehand for the case of low
~ 57 ~
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
_ FOR OFFICIAL USE ONLY
excitation levels, and the corresponding gains are set for tRe cross feed
_ devices driving the exciters.
= Another method of compensating for r_ro~stallt energ}* consists in generating
~z st~lbtlizing si~nal from the vibration action applied to the structure from ~n
zr 1.e,zst one exc~rer, r~nd in u~ing th~i.s signal to control the other exciters,
- (~'igure 24~, V~ctor 1 in Figure 59a represen~a the ampl~tude and phase of
the force acting on the product from one of the vibrators, vector 3 repre-
sents the action of the other vibrators at tRis po~nfi on the product; the
resulting action is depicted by~vector 2. In gigure 29b, vector 3 is
amplified so much vector 1 has a negative component, which corresponds to
the removal of power from the product by fihis vibrator. System operation
is unstable in this mode. Shown in Figure 29c is the method of generating
an additional vector 1a, which ccrmpensates for the negative component vector
l. If it is added to vector 1b, then tfie result i5 vector 1, shown in
Figure 29b. Vector 1a is the control vECtor. Tts direction is opposite to
the direction of the vector of the resulting vibrat~on 2, while its magnitude
should be such that vector lb is always directed to tfie right, i.e., it should
not have a negative component. Tt is shown in Fig~re 29d that the vectors
la, 3 and lb yield as the sum vector 2, wfiich corresponds to stable system
- operation thanks to the direction of vector 1b.
TABT.F. 5
The Technical Chracteristics of Vibrators
~t~ !R~:1KC{1~1.I:ILII.IH ;Nahcu~~u:ii,u:ia HC(~XIIAA hi.ihcu~~a.i~..
Tiin 1� Tnii uu~~by;~,^.;ic~+uA c~apucti~ rpa~urmaA twt ucpc~i~.
Clll'ICVLI BO't0).111TC:IH CIGI:I, KO:ICOJi)II1. 4ill'101~1, Wt111IC,
T~e 2, ti , 4. ru 5. _
?is-uisi n,s ~ - . s~o o.s
_ H$-I(10$ HE-I100 5000 1,3 10(1 50 �
IiS-IOIU HE-I?Q~ I~JOUO 0,65 ~
H 5-1030 . H E-130U 20 OOU l,? _
- iis-ioso tte-isnn so~oo i.o so
HS-III)Il Ht:-1600 100000 ~~,5 100
HS-!~~i0 HE-IR00 500000 0,2 30
Key: 1. Type of exciter;,
2. Maximum excitable force, N;
3. Maximum vibration speed, m/sec;
_ 4. Upper frequency limit, Hz;
5. Maximum travel, mm.
The methods of compensating for crosstalk energy considered above are labor
intensive in their execurion and require c~mplete automation for wider
introduction into vibration testing practi�ce.
' _ 5g _
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
Electrohydraulic vibrators are w~idely used in mulfi~channel systems as the
force exciters. Thus, for example, for tfie vibrat~on testing of motor
vehicles and railroad cars, as we11 as tests for vi~rational strength and
the experimental determination of tRe parameter~ of tfie natural resonant
oscillations in models of buildings and structures, hydraulic installations
have been designed by the "Chinken KO"' Company (Japan), which are intended
for operation in multicfiannel systems (Tab1e 5).
The "Inova" Company (Czechoslovakia) produces the EDYZ3-n and EDYZ4-n
electronic control equipment which is intended for the control of electro-
dyr?amic vibrators (1 - 4) during prograntmable dynazaie testing of structures
in accordance with a specified 1aw for the change of tfie acceleration in~a ~
frequency range of 0.03 - 300 Hz. Tfie control gear ~s equipped with a
programming unit and a photoelectric device for input from eight-track
punched tape.
Structures with distributed parameters (weight, stiffness, damping) are
studied by means oi multichannel sys~tems. To be numbered among these are
first of all complex equipment sets and their structural components, which
have a large number of natural resonant o:,�cillation forms. This special -
feature of the tests produces a number o~ addifiional requirements which are
placed on multichannel systems intended for studying fihe natural resonance
forms of the oscillations of a structure.
As a rule, the number of channels in such systems is significantly greater
than the number of channels in a vibration test system, something which
substantially complicates the testing procedure. Stricter requirements are
placed on the control equipment as regards tRe precis~on in setting the
requisit~ parameters. The 1eve1 controllers sRou~d assure a force setting
accuracy with an error of 0.5 percent, and ~or tl~is reason, multiturn wire .
potentiometers are frequently used as the 1eve1 controls as part of a set
with multichannel readout devices.
Increased requirements are likewise placed on phase controllers. For example,
the error in setting the phase should be less than 0.5 degrees. By using
potentiometers and readouts similar to those employed for the level control,
these requirements can also be met.
It is essential to reduce tRe influence of tfl;e viBration exciters, the vibra-
~.tors, on the parameters of tfle structure and the reaction o~ tTte structure
' � to the exr.itation of the force. gor this reason, the vit~rators sAould have
a minimal connected mass, while their suspension should have minimal stiff-
ness with respect to the weight and the stiffness of tfie element of the
structure L*ei'ng studied, to Frh~eh tRey~ are connected. These requirements
are met by electrodynamic vibrators with a light moving coi1, which have ~
a suspension system only ~or centering the moving system, and which are con-
nected to the structural element by means of lighfi tie rods. To be numbered
among the special features of these v~'bra~vrs are fiAe ~ride frequency range,
beginning at zero, and the higR linearity of the characteristic (about 1%):
� -59-
, FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
r= f(In), where F is the force which is developed; In is the current
in the moving coil in a wide dynamic r~ange (less than 60 dB). Moreover,
- there should be no phase shift between the current in the coil and the
push3ng force throughout the en~ire frequency range.
- All of the system components should remain linear during excitation. This
means, that even at resonant frequencies, the deformation of the structure
at any point in it should not exceed the limits o~ elastic deformation. To
obtain such exciting forces at resonant frequeneies, vibrators are required
having low forces. Thus, for e~ample, vibrators witA an output force of
1,000 - 2,000 N are uased to investigate such bulky structures as modern -
aircraft.
When mechanical oscillations of the structure are present at a natural
resonant frequency, the forces developed by the structural components, the
ma~s of wRich considerably exceeds tfie mass of tfie moving system of the
vibrator, coincide in phase and 1eve1 with the force excited by the vi-
brator at a"reference" point, i.e., with the force which was produced by
the mechanical oscillations of this structure. At all the remaining points,
the force developed by a structural element can in the general case consid-
erably exceed the force developed by the vibrator positioned at the given
point, and may not coincide with it in phase, i.e., the vibrator can be
placed in motion by an external force.
In vibrators which operate in a generator mode (~orced motion), a voltage
- is generated which does riot matcfi the phase and 1eve1 of the voltage (or
current) of the power ampli~ier. As a result, tfie overall voltage (or
current) of tP~e power amplifier can differ from the specified value, some-
thing which leads to a distortion of the study results.
In order for the moving system not to exert a mark.ed influence on the
excitation current with forced oscillations, the output impedance of the
~ ampliFier shou.ld be high. An ampli~ier whicR is a current generator, the �
outptie impedance of which amounts to tens of Kohms meets these requirements.
The choice of tE~e level and phase of tfie exciting forces o~ the vibrators,
where the overall number of forces is equal to three, is relatively simple,
but becomes considerably complicated when tReir num~er increases. The ideal
choice is possible only in the case wfiere the excitation points and the
directions of the excitation forces are chosen in such a manner that the
introduction of any additional exciter, with the appropriate regulation of
its force and stiffness (the excitation level and phase) can preclude the
excitation of at least oze additional tone. The position of the nodes of
the inter~ering tones and the direction of tAe excitaCion forces at the
start of the testing are not known precisely and are ascertained during the
- testing process. Tn those cases wliere the vibrators excite forces at
arbitrary points, tfie change in the force and stiffness o~ one vibrator
leads to a change in the force and stiffness at the remaining points of the
structure. The ''Prodera" Company~ (France) produces 2, 4, 8 and 16 channel
equipment, including the power suppl}r equi:pment, exc~tation control and
recording equipment. It also manufactures the equipment and exciters for
studying the structures of an aircraft in flight.
- 60 -
FOR OFk'ICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
Dua1 channel equipz~ent is intended for study~ing comparatively simple
assemblies and units (cranl~shafts, sp~ndles, spr~ngs, gear hoaes, etc),
as well as samples of materials when flexed, twisted or under tension
and compression. Tests for wear or rupture w~`_tR an alternat~ng load can
- be carried out using thi~ equipment.
Included in the equipment set are a generator and tuo exciters with power
amplifiers. The level control for the common channels ~s accomplished
by the output voltage of the generator, and in each of the channels by -
the gain of the power amplifiers. The amplifier phase can be varied by
180�. The system is designed in the structural con~iguration shown in
Figure 26.
- Such complex structures as motor vehicle campartments, aircraft, engines,
� etc. can be tested using four cltannel equipment. Such systems are composed
of a two-phase generator, excitation level.and phase control units, vibrat-
ors, power amplif iers and vibration analysis equipment. This equipment
includes vibrations transducers (for travel, velocity or acceleration), a
mult~_phase meter or the simultaneous observation o# 2Q I,issa~ous figures,
which determine the phase between the exciting force at LAe characteristic
points and the velocity of travel of these points, as We11 as units for
isolating tfle real and imaginary components of their coordinates.
In some cases, in particular, to study symmetrical structures, four exci-
tation points can be insufficient. Then eight-channel equipment is employed;
it includes two sets oP four-channel equipment.
[1 set of eight-channel equipment can include equipment for automatically
recording and processing tlie test results. Sixteen-efianne7. equipment is
also put together in a similar fasfiion, by means o~ whicA, one can carry
out any kind of investigation.
The 2, 4, S and 16-channel systems can be put together arith vibrators of -
different types. Depending on the complexity and the overall dimensions
of the structure, and the type of tests, the company recommends vibrators
of the following types:
1) When testing for fatigue life and general studies of heavy structures:
- 20IE20~- EX303; medium structures: EX303 - EX304; light structures:
EX304 - 20IE30;
2) For laboratory studies of a rigidly secured structure: 20IE40, and on
~ a breadboard model; 20TE30; in the case of h~gR.~requency tests: 20IE20.
The technical characteristics of tRe vibrators o~ the "Prodera" company are
given in Table 6.
Sys~ems for Multicomponent Vibration Effect Testing
The vibration test sy~stems wR~ePt Rave been considered are intended for gener-
- ating vibrations in one direction. Under actual conditions, the ma~ority of
- 61 -
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY �
TABLE 6. The Technical Characteristi:cs of fihe Vibrators of the "Prodera"
Ccrmpany .
. Mat~ct~~~anbxaa i~'I~1CC1 BC~!(HAA
~1~Tnn ~2~ T~m eo~'oyMaae>taa uoaeu�;uoG rpam~~maa Rcpcaiente~mc.
BU'lOy'~IITt.7A fCI1:Ii1lC.IR CIH~~ ~111CK0\Ibl~ ~~4:11''fOT~, Cr1\(
1 O
f:!C�497 4~)4,'30 , 5 0.01 600 5
_n1E~;C A-4?6 O,l 3U0
EX-30~1A '_'pWA50I1~ 10 0,033 ''00 l0
EX�]04C A-436 0,(12 1000
'_OIE40rB 20WASOJ~A 35 0,09 ZU00 5 .
EX-303A 2UWASO,T~A 0,0)5 1400
L�X-303,q . A-~94J3~ 50 0,17 1130
EX-303C A-336 0,15 1000
'_OIE30C .~�i36 0,32 350 10
''UIE'_'OB 391YA~OJ.~A :00 0,36 200
'_OIE?0~ A-438 U,26 1000
EX-356 20WASUT,.jA+FA 600 1,35 200 '
~ L�Y-4?OC �A-~?~+ 1000 3,0 150
EX.43pR ^_X~?~i38 4~ �
12
t:X-a20E =XA338 ?000 � 5,0 50
Key: l. Type of exciter;
- 2. Type c~f amplifier;
3. Maximum excitable force, N;
4. Weight of tlie moving sy~~em, kg;
5. Upper frequc~ncy limit, Hz;
6. Travel, mm.
products experience vibration loads in several directions. V3brations along
each axis of ~n arbitrarily chosen spatia~. system of coordinates have a dif-
ferent nature of the timewise change and a different degree of cross-correla-
tion between t:Rem. For the purpose of having test conditions approximate the
actual ones, it is c:ssential to have multicomponent vibrativn test stands
which reproduce the spatia~ vibration while meeting tfle requirements presen-
ted above.
- The motion of a solid in space is determined by six degrees oPfreedom:
three translational degrees in tRree mutually perpe~dicular directions and
three rotational ones about tfie coordinate axes of tRe translational motion.
-62-
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
Test stands which 7.imit the poss~~i~it~es o~ the motion of the body~ to t~ro
_ to three degrees of ~reedcrm are ~ssua~.ly~ e$p7,oy~ed i~?i v~bration test s}?~stems
_ (translati:onal motion of the 9od}r i,n two te tAree ~?mituall}r perpend~cular
directions or translational motion a7.ong one ea~s ~n con~unct~on w~tA rota
tion about this a~is, etc.). The structural design of the vibrators is con-
siderably complicated with an increase in the number of components. TRis is
related to the necessity of eliminating mutual influence ~etween the indi-
yidual components, something whicIi is acR~eved Dy~v~rtue of suBstantially~
complicating the structural design of a v~brator. Moreover, when the number
of components is increased, tP?e operational r~liab~lity fa11s off sRarply and
there arises the necessity of automat~ng the process of controll~ng and re-
cording the parameters Being Taeasured beeause of tfl~ great labor intensity
of manual control and recording of tAe parameters.
Multicomponent vibrators can be electromechanical, electrofiydraulic, electro-
dynamic and mixed types. I11 accordance aritfi this, the power supply and control
equipment for such vibrators is diverse in terms of its composition. Tt can
included control console~ with electric motors, pumps, direct current and
alterr~at~,~ng current power amplifiers, etc. Such vibra~ors are usually in~
tended for solving specific problems, and are rearely all-purpose types.
As a rule, they have a complex structural design and a limited working range
of frequencies and amplitudes.
T~ao and three component electromechanical type vibrators are known, which
generate harmonic dscillations in two to three mutually perpendicular direc-
tions in a range of frequencies up to 200 Hz. Dual component electrodynamic
type vibrators have been designed which reproduce longitudinal and torsional
oscillations independently of each other, in a wide range of frequencies
(longitudinal oscillat~ons of 2,000 Hz, angular oscillations of 500 Hz),
accelerations (longitudinal oscillations of 750 m/sec2, angular oscillations
of 3,000 deg/sec2) and displacPments (longitudinal displacements of 10 mm,
angular, + 7.5�) in accordance with an~y specified law. Tfiere are individual
examples of vibrators which fiave five to six degrees of freedom and operate
in a range of frequencies from 0.1 to 5 ftz with oscillation amplitudes of
less than 40 r~m.
Of the greatest interest are vibration test systems with multicomponent test
stands which consist of single component electrodynamic vibrators having a
_ common vibration platform. A block diagram of a system for reproducing three-
component v~bration is shown in Figure 30 which used electrodynamic vibrators,
which reproduce oscillations in three mutually perpendicular directions on tfie
X, Y and Z axes. The operation of electrodynamic vibrators 6x, 6y and 6z is
controlled by master generators 1 or programm~.ng racks 2x, 2y and 2z through
remote control panel 3. Eacfi vibrator can be controlled from the master units
of both types inde~ender_tl.y of eacfi other. When specifying the vibration frc~m
the programming racks, control is realized through a cross correlation instru-
ment for vibra~ion processes, 10, in which the regulation of the cross corre-
lation level of the vibration is accomplished along tfie X, Y and Z axes.
The moving coils of the vibrators ar.e powered froin power amplifiers 4x, 4y
and 4z. Besides the control equipment, th~s system includes spectrum
-63-
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9
~
FOR OFFICIAL USE ONLY .
analyzers for determining the spectral densities of the vibration accel- -
erations along the axes, as we11 as spectrum analyzers for the cross-corre-
lation gunctions Sx, 5y and 5z,
Figure 30. Block diagram of a system
for mul~icomponent vibra-
2z 1y 2z 3z tion testing.
Sy Key: 1. Control generators;
sx 2z,2y,2x. Programming devices;
3. Control panel; -
~ 4z 4z,4y,4x. Power amplifiers;
- ~ ~ 6z ~ 5z,5y,5x. Spectrum analyzers;
_ ~
6z,6y,6x. Vibrators;
t 4 j ~ I 7z,7y,7x. Vibration transducers;
~y 3 D sy ~~8 ~ 8. Attachment for fastening
4x i I the product;
~ I. I I
~ ~ 9. Bed on which the v~hra-
_ rx D L____6x_JJ tors are mounted;
1.0. Cross-correlat~on ~nstru-
~0 ment for the vibropro-
cessors.
The signals are fed to the analyzers from transducers 7 through the corres- ~
ponding meters, which are included in tRe complement of the programming
racks.
The ma~or component of this installation 3.s the vibration platform, the
structural design of wRich precludes mutual influence between components.
It is made in the form of a cube or three rigidly fastened, mutually per-
pendicular walls. The outer surfaces of the vibration platform are coupled
through special disks to the vibrators. The surfaces which are ad~acent to
the platform and the dis~C are ground and there is a layer of oil between
them. Rather great attractive forces (about 1 kgf/cm2) arise between such
svrfaces, and at the same time surfaces easily move wi~h respect to one
another. The influence of frictio:~al forces is small. Tt fias a pronounced
effect only at frequencies below 40 Hz and is absent at frequencies above _
100 Hz.
The advantages of the system considered here must include the presence of
a wide range of operational parameters, which is basically determined by
the technical characteristics of the electrodynamic vibrators used in the
system; also, the possibility of testing products in accordance with any
specified law; the universality of tRe system (tRe possibility of generating
a strictly unidirectional, plane or spatial); tfie possibility of specifying
and controlling the cross-correlation; and the absence of the necessity for
synchronizing the oscillations for each component.
- 6 4 - -
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007/02148: CIA-RDP82-00850R040200040015-9
I
FOR OFFICIAL USE ONLY
The Technical Characteristics of the ~ystem
The working frequency range, Hz 5- 3,000
The maximum e~ection force of the vibrators, N:
Vert~cal 50,000
Horizontal 6,000
The maximum acceleration developed by the vibrators,m/sec2:
_ Vertical 500
Horizontal 300
The maximum ampZitude of the vibrations, ~n 12
Piaximum load lifting capability without additional
weighting, kg 70
Bibliography
1. "Avtomaticheskoye upravleniye spektrom sluchaynykh vibratsiy na elektro-
dinamicheskikh vibrastendakh s pomoshch'yu ETsVM" ["Automatic Control of
_ of the Spectrum of Random Vibrations on Electrody~nami:c 'V~brat~.on Test
Stands by Means of Digital Co~puters"], TEORTY'A AVTOMATTCHESKOGO
UPRAVLENTYA [AUTOMATIC CONTROZ THEORY], K~ev, Ukrain3.an Academy of Sciences
Institute of Cybernetics Publishers, 1969, No 4, pp 53-67, Authors: A.G.
Getmanov, M.T. Sfiaposhnikova, 'V.F. Do1}ra, B.X~. Mandrovsk~y~Sokolov,
A.A. Tunik.
2. Bar.anov, V.N., Za~harov, X'u.Y`e~, "'~lektrogidravlichesk~ye v~brats~onnyye _
- mekhanizmy" j''Electrohydraul~c Vibration Mechan~sms'~'] , Mosco~r, Mashino-- _
stroyeniye Publishers, 1966, 243 pp.
3. Bendat, D.Zh., Pirsol, A., "Izmereniye i analiz sluchaynykh protsesso'v"
["The Measurement and Analysis of Randorn Processes"], Moscour, M:Lr Publ~-'
- shers, 1971, 464 pp.
- 4. Lenk, A., Ren.its, Yu., "Mekhanicheskiye ispytaniya priborov i apparatov"
["Mechanical Tests of Tnstruments and Equipment"], Translated from the
German by P.S. Boguslavskiy, Edited by P.T. BulovsItiy, Moscow, Mir
Publishers, 1976, 270 pp.
5. Makarov, O.M., "Raschet optimal~noy si.~temy formirovanipa ~pektra
sluchaynykh vibratsiy pri minimal'nom ch~,sle formiruyusAcRikh i analizi-
ruyushchikh fil'trov" ["The Design of an Optimal System for the Generation _
of Random Vibration ~pectra with a Min~num Number of Shaping and Analyz~ng
_ Filters"] , TEORTY'A A'VTOMATTCHE~K0~0 'UPRA'VT~ENTYA, Kiev, Ukrainian Academy
or Sciences Tnstitute of Cybernetics PuBlishers, 1969, No 2y pp 75-91. r
~
~ -~,T~
65 - ~
FOR OFFICIAL U5~ ONLY ~
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
6. Makarov, O.M., Mandrovskiy-Seko~av, B.Xu., "Issledovantye tochnosti
avtomaticheskoy sistemy upravleniya spektrami sluchaynykh vibratsiy"
["A Study of the Precision of an Automatic Control System for Random
Vibration Spectra"], TEORIYA AVTOMATICHESKOGO UPRAVLENIYA, K~ev=
Ukra~nian Academy of Sciences Institute of Cybernetics Publishers,
- 1969, No l, pp 35-36.
7. Serensen, S.V., Garf, M.Ye., Kuz'menko, V.A., "I~inamtka mashin dlya
ispytaniya na ustalost ["The Dynamics of Fatigue Testing Machines"],
Moscow, Mashinostroyeniye Publishers, 1967, 460 pp.
8. Uretskiy, Ya.S., Chabdarov, S:-~.M:, Leont'yev, V.V., "Mnogofunktsional'nyy
viUroizmeritel'nyy pribor" ["A Multifunction Vibration Measurement Ins-
trument"], in the collection, "Vibratsionnaya tekhnika. Materialy semi-
nara" ["Vibration Engineering. Seminar Papers"], Part 2, Moscow, MDNTP
_ imeni Dzerzhinskiy, 1970, pp 71-74.
~ 9. "Tsifrovaya sistemy formirovaniya, analiza i upravleniya spektrom =
sluchaynykh vibratsiy" ["A Digital System for Random Vibration Spectrum A
Generation, Analysis and Control"], in the collection, "Kibernetika i
Vychislitel'naya Tekhnika. Vyp. 16" ["Cybernetics and Computer Engineerir~ ~
ing, Vol 16"], Kiev, NauR.ova ~Dumka Publishers, 1972, pp 78-85, Authors:
A.A. Tunilc, V.N. Poyda, M.T. Lobovkin, N,K. Matviyenko.
1.0. Krendell., S.M., "Sluchaynyye koleUaniya" ["Random Oscillations"], Moscow,
Mir Publishers, 1967, 356 pp.
J.l.. Harris, C.M., Crede, C.E., "Shock and Vibration Handbook", Vol. I-III,
McGraw Hill, N.Y., 1961.
12. Nelson, D.B., "Performance and Methodology of a Digital Random Vibration
Control S~stem", Institute of Environmental Sciences, Annual Technical
Meeting Proceedings, 1973, pp 187-191.
CHAPTER 13. SYSTEMS FOR MEASURING AND ANA.LYZING VIBRATION, SHOCKS AND NOISE ~
Acoustic Noise I~easu~~ments Systems
Acoustic noise measurement systems mak~ it possible to study the effect of
acoustic noise on people and equipment, and to monitor and reduce its impact.
The noise level produced by a machine or mechanism depends on many factors,
and for this reason, it is recommended that noise be measured under acoustic-
- ally specified conditions, as indicated in the instruction of the International ~
Standards Organizatian, the ISO, on technical standards and specifications -
(ISO, Instructian R445). The acoustic noise power developed by a mechanism
can be assessed on the basis of ineasurement results. When measuring noise, -
three different types of an acoustic field are usually determined: the
acousticaJ.ly free field, the diffusion field and the sem~reverberating field.
- 66 -
FOR OFFICIAL USE ONLY -
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
Noise measurement and analysis systems are primar~ly used to determine the
acoustic Properties of a room and improve them; to ascertain the results of
the action of acoustic noise on equipment and personnel; in the field of
acoustics and communications to evaluate the quality of electrical acoustic
_ devices; and in research in physiological acoustics and acoustic measurements
in liquid media.
Acoustic noise measurement and analysis systems can be broken down into two
main groups to ascertain the results of the action of noise on equipment and
- personnel during the operation of equipment and during its testing. Included
_ in the first group are systems consisti`ng of portable and miniature equipment
for use in the field, and in the second, complex stat~�onary systems for use in
zesearch laboratories.
The simplest measurement system consists of a microphone and a preamplifier,
- placed on a tripod or stand, in whieh case, the preamplifier output is coupled
to the input of an instrumentation amplifier. The instrumentation amplifiers.
used in such systems usually contain A, B, C and D equalization circuits. The
simplest acoustic noise measurement system is realized in the domestica�lly pro-
duced "Shum 1" noise meter, as well as in the SPM101 noise meter (GDR). Such
- a system can be designed by using the equipment of tRe "Bruele and Koer" com-
. pany, for example, the 4145 microphone, the 2819 preamplifier, and the 2606
instrumentation amplifier.
To measure a noise dose, a system is used which takes the form of a combina-
- tion of a noise meter and a dosimeter or instrumentation amplifier with a
- dosimeter. Such a system is intended for estimating the equivalent level of
~ continuous sound in accordance with t&e requirements of domestic and inter-
- nat~ional s~andards.
The operation of a noise dosimeter is based on the principle of equal energy,
i.e. on the hypothesis where an equal noise dose is maintained, a reduction
in the sound 1eve1 by 3 dB is equivalent to doubling its duration. For exam- -
ple, the type 4423 noise dosimeter of the "Bruele and Koer" company operates
on this principle. The instrument, incorporated in a system, makes it possibLe _
- to evaluate the level of continuous sound in accordance with the requirements
set forth in ISO recommendations (R1966 and R1999) and in the DIN 45641 stand-
ard [German Industrial Standard]. Tt can also be used to estimate the noise
level and impact on people.
The following relationship is the basis for the operation of the 4423 noise
dosimeter:
T
L~~A - ~g z~g \ T J\ Po) ) 209
0
where L~HB is the equivalent continuous sound level; p(t) is the cariable
= sound pressure; po is a reference pressure, equal to 20 UN/m2; T is the
integration time; q is a parameter ~~iich describes the relationship between
-67-
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
the sound volume and its permissible duration, chosen equal to three based
on ISO and DIN standards.
Under field conditions, the acoustic noise is frequently recorded on magnetic
- tape by means of. portlble microphones. The recording is calibrated i~sinfi n
rcf.erence siPnal generated by a sound source using a piston in a ctosed cyl.in-
der [pistonphone] or by an acoustic calibrator. For the purpose of obtaining
operationally timely information on the frequency composition of the noise
t.~ing studied, a spectral analysis of tfte noise is frequen~tly made with octave
or one-third octave filters. ~
> 2 4 .
- b D l~'U
Figure 29. Block diagram of an acoustical noise
measurement system.
Key: l. Microphone;
2. Preamplifier;
3. Frequency spectrometer;
4. Autorecorder.
~i noisc~ measurement system with an ins~rumentation amplifier and a set of
bandr~i5s filters pcrmits more precise ineasurements and noise analysis under
steady-state conditions. The 2606, 2607 and 2608 instrumentation ampli.fiers
with the 1613, 1614, 1615 and 1616 bandpass filters (Denmark) can be used in -
the system. The 2608 and 2609 instrumentation an~plifiers are distinguished by
a built-in A equaZization circuit. The 2606 and 2604 amplifiers contain a
- peak value detector, a D equalization circuit and a11ow for the measurement of
puised sound in accordance with the requirements of the standard DIN 45633,
Part II, and the proposals of the Tnternational Electrical Engineering Commis-
sion. High values of the averaging time and a more refined rectifier circuit
are provided in the 2607 amplifier than in the other amplifiers. If it is
- possible to adjust the level of signal attenuation, for example, by providing
for a set of type 1613 filters, then noise level measurements in accordance
with a specified noise criterion is simplif ied, as we11 as the reading of the
maximum permissible noise level in each octave frequency band. The level of
attenuation of each filter is adjusted by an amount below the calibration level
by which the noise criterion exceeds it. The reading of the noise meter is
- limited so that the pointer falls below the mark on all of the filters. In
~ this case, it is not necessary to switcfi the attenuator for the noise meter
ranges.
A block diagram of a noise analysis and measurement system with a frequency
spectrometer is shown in Figure 29.
The "Messelektronik" People's Enterprise (GDR) recommends that such a system
be put together with MK102, MK201 and MK301 microphones, the PS1202 precision
sound level meter, tfie TOA111 one-third octave ana7~yzer and the PSG101
~ -68-
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY
autorecorder. The system makes it possible to record the frequency spectrum
of the noise on the chart paper of the autorecorder, in which case, the ana-
lyzer is mechanically coupled to the autorecorder. Because of this, one can
achieve agreement between the frequencies on the chart papex and the analyzer
- frequency. The range o~ frequenc~es of a system with the MK102 microphone is
from 20 Hz to 20 KHz, with the MK201 microphone, it runs from 30 Hz to 35 KHz,
and with the MK301 microphone, from 30 Hz t~ 40 KHz. The one-third octave
analyzer makes it possible to analyze noise in a range from 2 Hz up to 160 KHz; -
the measurable level range runs up to 140 dR.
Tlie 2113 or 2114 frequency spectrometers of the "Bruele and Koer" company -
- (Denmark) can be used in this system, where the center frequencies of the
filters of the 2113 instrument fall in a range of 25 Hz up to 20 KHz, while -
for the 2114 instrument, in a range of 2 Hz to 160 KHz. The passbands can be
_ chosen as octave or one-third octave band.s.
For narrow band noise analysis in tfie field, it is convenient to utilize the
2120 frequency analyzer which is powered from an external 12 volt DC source.
A statistical distribution analyzer, which in conjunction with the level auto-
recorder makes it possible to obtain acoustic noise histograms, is used in the
noise measurement system to study the statistical timewise distribution of ~he
noise levels, as well as the probability of finding noise in a specified range
of levels or the noise exceeding a set level.
A system can be designed, for example, using the equipment of the "Bruele and
Koer" company by employing the 2305 and 2307 1eve1 autorecorders, the 4420
statistical distribution analyzer, the 2606, 2607, 2608 or 2609 instrumenta-
tion amplifiers and the 4145 microphone with the 2619 preamplifier. The micro-
phone with the preamplifier is secured to a VA~049 tripod. Such a system is
u,ed to measure noise doses us~ng the methods recommended by the TSO. _
An analog reader ~r digital encoder is connected to the level autorecorder for
the analog to digital conversion of signal levels. The analog reader provides
~ for a DC output, the level of which is proportional to the mean square, peak,
or mean value of the sound signal being measured. The output from the analog
reader can be fed to an analog to digital converter, and then to a tape pun-
cher. A digital encoder feeds out data in binary-decimal code, which can be
fed to a taper puncher. In stationary systems, wide use is made of noise re-
cording on magnetic tape by means of instrumentation tape recorders or magneto-
graphs.
For the precise determination of the frequency components of noise, for ex-
ample, when studying acoustic noi:se produced by machines and mechanisms,
stationary systems with narrow band analyzers of two types are used: those
with a constant relative or a constant absolute width of the passband.
It is convenient to use an analyzer in real time for the measurement of noise
levels, their frequency analysis in octave and one-third octave bands, with
visual observation of the results under steady state conditions. In this
case, the noise spectrum is displayed directly on the screen of a cathode ray -
tube as light columns.
-69-
FOR OFFICIAL USE ONLY
APPROVED FOR RELEASE: 2007/02/08: CIA-RDP82-00850R000200040015-9

APPROVED FOR RELEASE: 2007102/08: CIA-RDP82-00850R000200040015-9
FOR OFFICIAL USE ONLY ~
~For the detailed analysis of audio signals, it is expedient to employ a
l34$ real time, narrow band analyzer (of the "Bruele and Koer" company),
which contains 400 filters with a constant bandwidth. The spectrum bein~
studied in the selected range is displayed on the screen of the CRT in the
form of narrow lines, the number of which is equal to the number of filters.
This spectrum is recorded in digital or analog form.
A computer can be employed to estimate the loudness of a sound, and compute
ttie level of the perceived sound in decibels and the sound power.
~ Figure 30. Block diagram of a multi-
~ channel system for measuring sound power
2~~ 3 in an anechoic chamber.
~2~~ J Ke 1. Anechoic chamber�
Z~` Z y� 2. Microphones; ~
~ 6 3. Power supplies for the micro-
3 phones;
. 4 S 4. Channel switcher;
3 5. Real time analgzer; ~
~ fi. Ana7.}*zer indicator;
~ 7. Level autorecorder; .
8. Object being studied.
3
~
When me