MIL-DTL-83361B
TABLE IV. Sinusoidal test schedule.
Number of resonances
0
1
2
3
4
Total vibration time at resonance
0
30 minutes
1 hour
1-1/2hours
2 hours
Cycling time
3 hours
2-1/2 hours
2 hours
1-1/2 hours
1 hour
NOTES:
1. The total vibration time at each resonance shall be 30 minutes.
2. The above time durations apply to testing along one axis only; three axes are required for a complete test.
4.5.9.1 Sinusoidal cycling and resonance conditions. The order in which the cycling and
resonance portion of this test are conducted shall be optional. The pointer shall be set at each of
the following indications for 1 hour during vibration along each axis:
a. 20 psi.
b. 50 psi.
c. 80 psi.
NOTE: Resonant modes of the specimen shall be determined by slowly varying the frequency
between the limits of 5 Hz and 500 Hz at an amplitude of applied vibration not exceeding that
shown by the cycling test curve. When dynamically complex test fixtures or equipment are
involved, low input vibration levels shall be employed to avoid unnecessary failures during the
resonance search. The resonances selected for this test shall be those that are most likely to
produce failure. If more than four resonances are encountered with vibration applied along any
one axis, the four most severe resonances shall be selected for testing. Should any functional
out-of tolerance conditions occur during the cycling test, one of the resonances tested shall be at
the frequency at which the worst out-of-tolerance condition occurred. If a change in the
resonance frequency occurs during the resonance dwell, the time of occurrence shall be noted
and the frequency shall be adjusted immediately to maintain the peak resonance condition. The
final resonance frequency shall be recorded.
4.5.9.2 Test procedure.
4.5.9.2.1 Cycling. The indicator shall be vibrated from 5 Hz to 500 Hz and back to 5 Hz
4.5.9 2.2 Resonance. The indicator shall be vibrated in accordance with the resonant
conditions and at the amplitude shown in figure 6, curve A.
4.5.9.2.3 Indicator operation. Operation of the indicator shall be monitored for
compliance with table III. If an out-of-tolerance condition occurs, the indicator shall be
subjected to and shall meet the requirements of 4.5.9.2.4.
4.5.9.2.4 Functional demonstration test. A functional demonstration test shall be
conducted at the conclusion of testing in each axis with the indicator operating. It shall operate
within the tolerances specified in table III. The frequency shall be varied from 5 Hz to 500 Hz
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