Downloaded from https://www.everyspec.com MIL-STD-810D 19 July 1983 TABLE 519.3-I. d uarametric eaua uced vibratim. 10log Tj=lOlog(NFIE)+H +M+W+J+Bj-53dB 10 10g Pi = 10 log T3 + Ki + 17dB Where: N . Maximum number of closely spaced guns firing together. For guns that are dispersed on the host aircraft, such as in wing roots and in gun pods, separate vibration test spectra are determined for each gun location. The vibration levels, for teat purposes, are selected for the gun thst produces the maximum vibration levels. E = Blast energy of gun (see table 519.3-III). H = Effect of gun standoff distance (see figure 519.3-4). :
M Effect of gun location M = O unless a plane normal to the axis of the gun barrel and located at the muzzle of the gun doea not intersect the airci’aftstruoture, then M . -6 dB. w = Effect of the weight of the equipment to be tested (use figure 519.3-5). If weight of equipment is unknown, use W . 4.5 kilograms. J = Effect of equipment’s location relative to air vehicle’s skin (use figures 519.3-2 and 519.3-6). Bj = Effect of vector distance from gun muzzle to equipment location (ace figure 519.3-7). F1 =;Gunfiring rate where F1 = fundamental frequency from table 519.3-II. (F2= 2F1, F3=3F1, F4=4F1) Tj . Test level in g2/Hz. Pi ’Test level for frequency Fi in g2/Hz (where i = 1 to 4).
Ki = Effeet of vector distance’on each vibration peak, Pi (see figure 519.3-8). NOTE: These equations are in metric units. The resultant dB values are relative to 1 g2/Hz. METHOD 519.3 19 July’1983 519.3-5