Downloaded from https://www.everyspec.com MIL-STD-81OD. 19 JUIY 1983 11-3.2 Frocetie 11 - EC@JMSent to be Step 1. Following the’guidance of paragraph I-3.4C, oalibrate the shock machine as follows: .,. a. Mount the calibration load (the actual test item, a rejected item, or a rigid dummy maas) to the test apparatus in a manner similar to that of the actual test item. Use a fixture similar in shape and configuration to the shock attenuation system which will support the teat item in its shipping container. (The fixture shouldbe as rigid aa possible to prevent distortion of the ‘shockpulse imparted to the test item.) . b.
Perform calibration shocks until two consecutive shock applications to the calibration load produce waveforms which are all within the tolerance envelope of the specified waveform (figure 516.3-5). Step 2: Remove the calibrating load and install the actual “testitem on the shock apparatus. Step 3. Perform a functional test on the test item. Step 4. Subject the test item to the test pulse. Step’5. Record necessary test data. This shall include test setup photoa, test logs, and photos of the actual test pulse. Step.6. Perform a functional test on the test item.’ Step 7. Repeat atepa 2, 3, 4, and 5 once in each directiori” for three orthogonal axes (six shooks). Step 8. Document results.
II-3.3 Erocedure III - prag.UUy .. Step 1. Install the test item on the shock apparatus using a fixture similar in shape and con?igu’rationto the shock attenuation system which will support the teat item‘in its shipping container. (The fixture should be as rigid as possible to prevent distortion of the shock pulse imparted to the test item.) Step 2. Select the design drop height,from paragraph I-3.5c. , .- Step 3. Adjust the shock apparatus to obtain a maximum test item velocity change obtained from measu~d data or as given in table 516.3-I. If maximum test item velocity change values are.required for deeign drop heights other than those listed, the following relationship may be used.
k AV = 2-) > impact velocity and rebound vel~citv) The the where A V = maximum test item velocity change. cmls (in/s) (summation of . :: ?xh:b%) ‘in) ,, drop height of the shock test apparatus design drop height. will not necessarily be the same as 516.3-21 MSTHOD “516.,3 19.July 1983