Материал: Стандарт MIL-STD-202G
MIL-STD-202G
METHOD 201A
VIBRATION
1.PURPOSE. The vibration test is used to determine the effects on component parts of vibration within the predominant frequency ranges and magnitudes that may be encountered during field service. Most vibration encountered in field service is not of a simple harmonic nature, but tests based on vibrations of this type have proved satisfactory for determining critical frequencies, modes of vibration and other data necessary for planning protective steps against the effects of undue vibration. Vibration, by causing loosening of parts or relative motion between parts in the specimen, can produce objectionable operating characteristics, noise, wear, and physical distortion, and often results in fatigue and failure of mechanical parts.
2.PROCEDURE. Prior to vibration, the specified tests or measurements shall be made. The specimens shall be mounted as specified using suitable mounting apparatus to assure that mounting is free from resonances over the test frequency range. The specimens shall be subjected to a simple harmonic motion having an amplitude of 0.03 inch (0.06 inch maximum total excursion), the frequency being varied uniformly between the approximate limits of 10 and 55 hertz (Hz). The entire frequency range, from 10 to 55 Hz and return to 10 Hz, shall be traversed in approximately 1 minute. Unless otherwise specified, this motion shall be applied for a period of 2 hours in each of 3 mutually perpendicular directions (total of 6 hours).1/ If applicable, this test shall be made under electrical-load conditions.
3.MEASUREMENTS. The specified measurements shall be made during and after vibration.
4.SUMMARY. The following details are to be specified in the individual specification:
a.Tests and measurements prior to vibration (see 2).
b.Method of mounting (see 2).
c.Duration of vibration, if other than that specified (see 2).
d.Direction of motion, if other than that specified (see 2).
e.Electrical-load conditions, if applicable (see 2).
f.Tests and measurements during and after vibration (see 3).
1/ In the previous issue of this method, test conditions A and B referred to a length of test of 5 hours and 2-1/2 hours, respectively.
METHOD 201A
24 October 1956
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MIL-STD-202G
METHOD 202D
SHOCK
(SPECIMENS WEIGHING NOT MORE THAN 4 POUNDS) (CANCELED)
When method 202 is specified |
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Use test method 213 |
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Test condition |
g (peak values) |
Test condition |
g (peak values) |
Waveform |
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A |
15g (pk) |
K |
30g |
(pk) |
Sawtooth |
B |
30g (pk) |
H |
75g |
(pk) |
Sawtooth |
C |
50g (pk) |
I |
100g |
(pk) |
Sawtooth |
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METHOD 202D 16 April 1973
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