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The Shock and Vibration Bulletin - Part 3; Acoustic and Vibration Testing, Impact and Blast

INTRODUCEION 
The electronic c•lexity Of tactical 
missiles 13 such a Ehzrough Etmctlonal 
checkout under vibration {g required the 
full mig sne assnbly level during engineering 
development. Typically such electrical checkout 
fecillt{eg do not include Large dedicated 
electrcdyne•mle drivers for v1brutLon testing. 
This hag brought about the need for 
a portable, simple to use and lov cost 
vibration system EO approximete 
three axis broadband randm flight vibration 
for tactical 
MISSILE FLIG}C VIBRATION 
The vibration experienced In flight by 
tactical missileg characterized as 
having broadband random waveform. Randm 
vibration Lc typically described In terms of 
acceleration spectral density The ASD 
{s the mean square acceleration per band— 
width as a function Of frequency. 
The ASD of Evo samples OE vibrntim 
measured on a version of Stendard Higsne are 
presented in Figure 1. 
ahe vibration xasure- 
menu. one of which In the redial (flight 
vertical) direction and the other of which ig 
In the ImgiEudLnaI direction, gere made 
Endevco 2221 D aece1ermeEer8 located on the 
Inside diameter of the airfrarm The acceler— 
oæters vere attached, us{ng 8 small Mtmeing 
block, to a region in the mid-gection of the 
nisgile which {s on the order of 13 millimeters 
(0.5 Inches) thick. The missile vibration 
data Vere transmitted durLng flisht using an 
telemetry system VIEh a data band*idth of 
20 to 5000 Rz for the vibration channels. 
Of the observations that can 
be made Erm the flight vibration 
dete that there considerable Ereqt*ncy

content above the typical vibration specifi- 
cation upper frequency OE 2000 KZ. 
PNENTIC VIBRATORS 
The checkout at 
General Dynamics, Poanna Division have u.ed a 
three diænsional hydraulic shaker system for 
nearly Eveney years. The shaker system, 
vas inside an empty rockee motor, Vas 
capable OE 136 kllograms (300 pomds) peak 
sinusoidal force capability at frequencies up 
to 600 Rz. The shaker system noraally took a 
ull gh{ft to set up and required considerable 
maintenance. When the vibration require— 
menu for broadband random waveform end an 
extended frequency coneent matured, the 
poeR{b11iEy of using pneLnetic vibrators vas 
explored.