204D
METHOD
VIBRATION, HIGH FREQUENCY
1. PURPOSE. The high frequency vibration test is performed for the purpo of determining the effect on
component parts of vibration in the frequency ranges of 10 to 500 hertz (Hz), 10 to 2,000 Hz or 10 to 3,000 Hz, as
may be encountered in aircraft, missiles, and tanks. The choice of test condition A, B, C, D, E, F, G, or H should be
bad on the frequency range and the vibration amplitude dictated by the applications of the component under
consideration, and the state of the component part in relation to resistance-to-vibration damage.
2. PROCEDURE.
2.1 Mounting. The specimens shall be mounted as specified. For specimens with attached brackets, one of the
vibration test directions shall be parallel to the mounting surface of the bracket. Vibration input shall be monitored on
the mounting fixture in the proximity of the support points of the specimen.
2.2 Test condition A (10g peak). The specimens, while deenergized or operating under the load conditions
specified, shall be subjected to the vibration amplitude, frequency range, and duration specified in 2.2.1, 2.2.2, and
2.2.3, respectively (e figure 204-1).
2.2.1 Amplitude. The specimens shall be subjected to a simple harmonic motion having an amplitude of either
0.06-inch double amplitude (maximum total excursion) or 10 gravity units (g peak), whichever is less. The tolerance
on vibration amplitude shall be ±10 percent.
2.2.2 Frequency range. The vibration frequency shall be varied logarithmically between the approximate limits of
10 and 500 Hz (e 2.10), except that the procedure of method 201 of this standard may be applied during the 10 to
55 Hz band of the vibration frequency range.
2.2.3 Sweep time and duration. The entire frequency range of 10 to 500 Hz and return to 10 Hz shall be traverd
in 15 minutes. This cycle shall be performed 12 times in each of three mutually perpendicular directions (total of 36
times), so that the motion shall be applied for a total period of approximately 9 hours. Interruptions are permitted
provided the requirements for rate of change and test duration are met. Completion of cycling within any parate
band is permissible before going to the next band. When the procedure of method 201 of this standard is ud for
the 10 to 55 Hz band, the duration of this portion shall be the same as the duration for this band using logarithmic
cycling (approximately 1-1/3 hours in each of three mutually perpendicular directions).
2.3 Test condition B (15g peak). The specimens, while deenergized or operating under the load conditions
specified, shall be subjected to the vibration amplitude, frequency range, and duration specified in 2.3.1, 2.3.2, and
2.3.3, respectively (e figure 204-1).
2.3.1 Amplitude. The specimens shall be subjected to a simple harmonic motion having an amplitude of either
0.06-inch double amplitude (maximum total excursion) or 15g (peak), whichever is less. The tolerance on vibration
amplitude shall be ±10 percent.
2.3.2 Frequency range. The vibration frequency shall be varied logarithmically between the approximate limits of
10 to 2,000 Hz (e 2.10), except that the procedure of method 201 of this standard may be applied during the 10 to
55 Hz band of the vibration frequency range.
描写竹的诗2.3.3 Sweep time and duration. The entire frequency range of 10 to 2,000 Hz and return to 10 Hz shall be
张海迪的故事
traverd in 20 minutes. This cycle shall be performed 12 times in each of three mutually perpendicular directions
(total of 36 times), so that the motion shall be applied for a total period of approximately 12 hours. Interruptions are
permitted provided the requirements for rate of change and test duration are met. Completion of cycling within any
parate band is permissible before going to the next band. When the procedure of method 201 of this standard is
ud for the 10 to 55 Hz band, the duration of this portion shall be the same as the duration for this band using
logarithmic cycling (approximately 1-1/3 hours in each of three mutually perpendicular directions).
204D
METHOD
1 April 1980
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G = .0512f2DA (f = frequency in hertz, DA = double amplitude in inches.)
FIGURE 204-1. Vibration-test curves.
METHOD 204D
1 April 1980
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2.4 Test condition C (10g peak). The specimens, while de-energized or operating under the load conditions
specified, shall be subjected to the vibration amplitude and frequency range shown on figure 204-1. The tolerance on
vibration amplitude shall be ±10 percent.
2.4.1 Part 1. The specimens shall be tested in accordance with method 201 of this standard for 6 hours; 2 hours in
each of three mutually perpendicular directions.
2.4.2 Part 2. The specimens shall be subjected to a simple harmonic motion having an amplitude varied to
maintain a constant peak acceleration of 10g (peak), the frequency being varied logarithmically between the
approximate limits of 55 and 2,000 Hz (e 2.10). The entire frequency range of 55 to 2,000 Hz (no return sweep)
shall be traverd in 35 ±5 minutes, except that in the vicinity of what appears to be resonance, and in order to
facilitate the establishment of a resonant frequency, the above rate may be decread. If resonance is detected,
specimens shall be vibrated for 5 minutes at each critical resonant frequency obrved. This procedure shall be
performed in each of three mutually perpendicular directions. Interruptions are permitted provided the requirements
for rate of change and test duration are met.
2.4.3 Resonance. A critical resonant frequency is that frequency at which any point on the specimen is obrved
to have a maximum amplitude more than twice that of the support points. When specified, resonant frequencies shall
be determined either by monitoring parameters such as contact opening, or by u of resonance-detecting
instrumentation.
2.5 Test condition D (20g peak). The specimens, while de-energized or operating under the load conditions
specified, shall be subjected to the vibration amplitude, frequency, range, and duration specified in 2.5.1, 2.5.2, and
2.5.3, respectively (e fig. 204-1).
2.5.1 Amplitude. The specimens shall be subjected to a simple harmonic motion having an amplitude of either
0.06-inch double amplitude (maximum total excursion) or 20g (peak), whichever is less. The tolerance on vibration
amplitude shall be ±10 percent.
2.5.2 Frequency range. The vibration frequency shall be varied logarithmically between the approximate limits of
10 to 2,000 Hz (e 2.10), except that the procedure of method 201 of this standard may be applied during the 10 to
丁渭
脚注的格式55 Hz band of the vibration frequency range.
2.5.3 Sweep time and duration. The entire frequency range of 10 to 2,000 Hz and return to 10 Hz shall be
traverd in 20 minutes. This cycle shall be performed 12 times in each of three mutually perpendicular directions
(total of 36 times), so that the motion shall be applied for a total period of approximately 12 hours. Interruptions are
permitted provided the requirements for rate of change and test duration are met. Completion of cycling within any
parate band is permissible before going to the next band. When the procedure of method 201 of this standard is
ud for the 10 to 55 Hz band, the duration of this portion shall be the same as the duration for this band using湖南瑶族
logarithmic cycling (approximately 1-1/3 hours in each of three mutually perpendicular directions).
2.6 Test condition E (50g peak). The specimens, while de-energized or operating under the load conditions
specified, shall be subjected to the vibration amplitude, frequency, range, and duration specified in 2.6.1, 2.6.2, and
2.6.3, respectively (e figure 204-1).
2.6.1 Amplitude. The specimens shall be subjected to a simple harmonic motion having an amplitude of either
0.06-inch double amplitude (maximum total excursion) or 50g (peak), whichever is less. The tolerance on vibration
amplitude shall be ±10 percent.
2.6.2 Frequency range. The vibration frequency shall be varied logarithmically between the approximate limits of
10 and 2,000 Hz (e 2.10), except that the procedure of method 201 of this standard may be applied during the 10
to 55 Hz band of the vibration frequency range.
乘公交车英文
204D
METHOD
金鹰节2016
1 April 1980
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2.6.3 Sweep time and duration. The entire frequency range of 10 to 2,000 Hz and return to 10 Hz shall be traverd in 20 minutes. This cycle shall be performed 12 times in each of three mutually perpendicular directions (total of 36 times), so that the motion shall be applied for a total period of approximately 12 hours. Interruptions are permitted provided the requirements for rate of change and test duration are met. Completion of cycling within any parate band is permissible before going to the next band. When the procedure of method 201 of this standard is ud for the 10 to 55 Hz band, the duration of this portion shall be the same as the duration for this band using logarithmic cycling (approximately 1-1/3 hours in each of three mutually perpendicular directions).
2.7 Test condition F (20g peak). The specimens, while de-energized or operating under the load conditions specified, shall be subjected to the vibration amplitude, frequency range, and duration specified in 2.7.1, 2.7.2, and 2.7.3, respectively (e figure 204-1).
2.7.1 Amplitude. The specimens shall be subjected to a simple harmonic motion having an amplitude of either 0.06-inch double amplitude (maximum total excursion) or 20g (peak), whichever is less. The tolerance on vibration amplitude shall be ±10 percent.
2.7.2 Frequency range. The vibration frequency shall be varied logarithmically between the limits of 10 and 3,000 Hz (e 2.10), except that the procedure of method 201 of this standard may be applied during the 10 to 55 Hz band of the vibration frequency range.
2.7.3 Sweep time and duration. The entire frequency range of 10 to 3,000 Hz and return to 10 Hz shall be traverd in 20 minutes. This cycle shall be performed 12 times in each of three mutually perpendicular directions (total of 36 times), so that the motion shall be applied for a total period of approximately 12 hours. Interruptions are permitted provided the requirements for rate of change and test duration are met. Completion of cycling within any parate band is permissible before going to the next band. When the procedure of method 201 of this standard is ud for the 10 to 55 Hz band, the duration of this portion shall be the same as the duration for this band using logarithmic cycling (approximately) 1-1/3 hours in each of three mutually perpendicular directions.
2.8 Test condition G (30g peak). The specimens, while deenergized or operating under the load cond
itions specified, shall be subjected to the vibration amplitude, frequency range, and duration specified in 2.8.1, 2.8.2, and 2.8.3, respectively (e figure 204-1).
2.8.1 Amplitude. The specimens shall be subjected to a simple harmonic motion having an amplitude of either 0.06-inch double amplitude (maximum total excursion) or 30g (peak), whichever is less. The tolerance on vibration amplitude shall be ±10 percent.
2.8.2 Frequency range. The vibration frequency shall be varied logarithmically between the limits of 10 and 2,000 Hz (e 2.10), except that the procedure of method 201 of this standard may be applied during the 10 to 55 Hz band of the vibration frequency range.
2.8.3 Sweep time and duration. The entire frequency range of 10 to 2,000 Hz and return to 10 Hz shall be traverd in 20 minutes. This cycle shall be performed 12 times in each of three mutually perpendicular directions (total of 36 times), so that the motion shall be applied for a total period of approximately 12 hours. Interruptions are permitted provided the requirements for rate of change and test duration are met. Completion of cycling within any parate band is permissible before going to the next band. When the procedure of method 201 of this standard is ud for the 10 to 55 Hz band, the duration of this portion shall be the same as the duration for this band using logarithmic cycling (approximately) 1-1/3 hours in each of three mutually perpendicular directions.
METHOD 204D
1 April 1980
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2.9 Test condition H (80g peak). The specimens, while de-energized or operating under the load conditions specified, shall be subjected to the vibration amplitude, frequency range, and duration specified in 2.9.1, 2.9.2, and 2.9.3, respectively (e figure 204-1). 2.9.1 Amplitude. The specimens shall be subjected to a simple harmonic motion having a constant amplitude of
either 0.06-inch double amplitude (maximum total excursion) or 80g (peak), whichever is less. The tolerance on vibration amplitude shall be ±10 percent. 2.9.2 Frequency range. The vibration frequency shall be varied logarithmically between the limits of 10 and 2,000
Hz (e 2.10), except that the procedure of method 201 of this standard may be applied during the 10 to 55 Hz band of the vibration frequency range. 2.9.3 Sweep time and duration. The entire frequency range of 10 to 2,000 Hz and return to 10 Hz shall be
traverd in 20 minutes. This cycle shall be performed 12 times in each of three mutually perpendic
ular directions
(total of 36 times), so that the motion shall be applied for a total period of approximately 12 hours. Interruptions are
permitted provided the requirements for rate of change and test duration are met. Completion of cycling within any parate band is permissible before going to the next band. When the procedure of method 201 of this standard is
ud for the 10 to 55 Hz band, the duration of this portion shall be the same as the duration for this band using logarithmic cycling (approximately) 1-1/3 hours in each of three mutually perpendicular directions. 2.10 Alternate procedure for u of linear in place of logarithmic change of frequency. Linear rate of change of
frequency is permissible under the following conditions: a. The frequency range above 55 Hz shall be subdivided into not less than three bands. The ratio of the
公务车maximum frequency to the minimum frequency in each band shall be not less than two.
b. The rate of change of frequency in hertz per minute (Hz/min) shall be constant for any one band.
c.
The ratios of the rate of change of frequency of each band to the maximum frequency of that band shall be approximately equal.
2.10.1 Example of alternate procedure. As an example of the computation of rates of change, assume that the frequency spectrum has been divided into three bands, 55 to 125 Hz, 125 to 500 Hz, and 500 to 2,000 Hz, in
accordance with 2.10a. Let the (constant) ratio of rate of frequency change in Hz/min, to maximum frequency in Hz
be k for each band. Then the rates of change for the three bands will be 125k, 500k, and 2,000k, respectively. The times, in minutes, to traver the three frequency bands will therefore be respectively: 125 − 55 500 − 125 2000 − 500 55k , 500k , 2,000k
Since the minimum total sweep time is 30 minutes, 70 375 1,500
30 =
++ 125k 500k 2,000k
from which: k = 0.0687 The required maximum constant rates of frequency change for the three bands are therefore 8.54, 34.4, and 136.6 Hz/min, respectively. The minimum times of traver of the bands are 8.2, 10.9, and 10.9 minutes, respectively. METHOD 204D 1 April 1980 5
3. MEASUREMENTS. Measurements shall be made as specified.
4. SUMMARY. The following details are to be specified in the individual specification:
a. Mounting of specimens (e 2.1).
b. Electrical-load conditions, if applicable (e 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, and 2.9).
c. Test condition letter (e figure 204-1).
d. Method of determining resonance, if applicable (e 2.4.3).
e. Measurements (e 3).
METHOD 204D
1 April 1980
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