Downloaded from https://www.everyspec.com MIL-STD-810D 19 July 1983 METHOD 515.3 ACOUSTIC NOISE Ea&e SECTION I I-1 I-2 I-3 PURPOSE .. ... . . . . . . . . . . . . . . . ...515.3-1 ENVIRONMENTAL EFFECTS . . . . . . . . . . . . . . . . . 515.3-1 GUIDELINES FOR DETERMINING TEST .PROCEDURESAND TEST CONDITIONS . . . . . . . . . . . 515.3-1 SPECIAL CONSIDERATIONS . . . . . . . . . . . . . . . . 515.3-4 REFERENCES .. . . . . . . . . . . . . . . . . . . ....515.3-6 SECTION 11 I-4 I-5 II-1 11-’2 II-3 II-4 APPARATUS ... . . . . . . . . . . . . . . . . . . .. ’. 515.3-13 PREPARATION . . . . . . . . . . . . ..” .. . . . . . .515.3-13 . PROCEDUFfES . . . . . . . . . . . . . . . . . . . . . .
515.3-14 INFORMATION TO BE RECORDED . . . . . . . . . . . . . . 515.3-16 SECTION I I-1. w=. The acoustic noise test is conducted to measure how well a piece of equipment will withstand or operate in intense acoustic noise fields. The acoustic noise test complements tests for structure-borne vibrations (method 514). o 1-2. ~. Acoustic noise can produce vibration in equipment similar to that produced by mechanically transmitted vibration. In an acoustic noise field, pressure fluctuations impinge directly on,the equipment. The attenuation effects of mechanical transmission are missing and the response of the equipment can be significantly greater.
Further, components which are effectively isolated from mechanical transmission will be excited directly. Examples of acoustically induced problems: a. Failure of microelectronic component lead wires. b. Chafing of wires. c. Cracking of printed circuit boards. d. Malfunction/failureof waveguides, Klystron tubes. _- - e. Vibration of optical elements. ~ I-3. This test method should be applied at the end of the tailoring process described in section 4 cf this standard. * a. A@i@+im. The acoustic noise test applies to any equipment operated Or stored in the intense acoustic noise field,qthat occur in or near aircraft, missiles, and large machinery such as pumps and generators.
In particular, it applies to: (1) Internally-carried airborne eq~ipment 515.3-1 NETHOD 515.3 19 July 1983