I MIL-STD-810D Downloaded from https://www.everyspec.com 19 July 1983 d. Test var~. The tests vary in apparatus, axes of test, and stress levels applied. I I-3.1 f!hoiceof est rm’ocedura& t Method 516.3 is divided into nine procedures: @ a. b. Functional shock (Procedure I) Equipment to be packaked (Procedure II) Fragility (Procedure 111) Tranait drop (Procedure IV) c. d. e. f. s. h. i. Crash hazard (Procedure V) Bench handling (Procedure VI) Pyrotechnic shock (Procedure VII) Rail impact (Procedure VIII) Catapult launch/arrested landing (Procedure IX) To find out whether a procedure is applice’ble,see subparagraphs‘a and b of the discussion of each procedure in this section.
All shock environments anticipated for the test item during its life cycle,,both in its logistic and operational modes, should be considered. The severity cf one type of shock may obviate the need to perform another type of shock test, but the configuration of the test item during these tests must be considered thoroughly before making this decision. I-3.2 mice of related test c~. . . Guidance for setting values for test conditions is found in this section in eubDaraEraDhs b, c, and d of the discussion of each procedure. I-3.3 e I- Fu@J.sIMd&h@.c Asdlcatmn .
Procedure I is intended to test equipment assemblies (incl~ding mechanica;, electrical, hydraulic, and electronic) in their functional mode. b. Reatrlcta. . . This test procedure will not be required along any axis for which a sufficiently severe random vibration test procedure is required, provided that equipment operational requirements are comparable. Random test severity is sufficient if its shock response spectrum, baaed upon a three-sigma Gaussian acceleration response of single degree of freedom (sdof) systems, exceeds the shock test response spectrum everywhere in the specified range of natural frequencies.
The quality factor Q (damping‘magnificationfactor or transmissibility at resonance) to be employed is ten, which is equivalent to five percent of critical viscous damping. The three-sigma shock response spectrum for the random test is given, as a function of natural frequency of :, the sdof system, by 3 ( /2)G(f)fQ in units of acceleration, where G(f) is acceleration spectral density (ASD) at frequency f (reference a). A comparison of the shock response levels found in figure 5?6,3-1 with ASD levels is found in figure 516.3-z. : c. Iest cq@a_QQa .t. (1) Slwck =@ trum and transient duration.
The shock response spectrum and the effective transient duration shall be derived from measurements of the te$t item1s functional environment, or from dynamical y scaled measurements of a similar environment, if available. METHOD 516..3 19 July 1983 516.3-2