Downloaded from https://www.everyspec.com MIL-STD-81OC 3.3.1 Determination of the O dB level. The O dB level for the sine and random vibration is defined by the following equations. Gos = rs E/Eo r/ro n/no (I) Gor = rr E/Eo r/ro n/no (2) G0s = O dB vibration level, mean squared g, sine (g*) G or = O dB vibration level, accel. power spectral !., density (g2/Hz) E = blast energy of gun (ft-lbs/gun) = . ~n firing rate (Hz) n = number of guns E.
= blast energy of reference gun (M-61) = 55,000 ft-lbs/gun no=l ro = gunfire rate of reference gun = 100 Hz rs = maximum sine vibration level of reference gun = 2,000 mean squared g (g2) r= = maximum random vibration level of reference gun = 35 g2/Hz A shortened form of (1) and (2) results when the reference parameters are inserted. G 0s = 3.64 x 10:4 E r n (la) Gor= 6.36 x 1o-6 E rn (2a) 3.3.1.1 Determination of the gun blast energy (E). The gun blast energy . is determined by the following equation. E = fWc/.3 - mv2/2 (3) f= WC . weight/round Of ~mUnitiOn SpeCifiC iIIIpetUSOf eXplOSiVe (ft/lbS/lb) (lb/rd) ~. Wp/g = mass of projectile (lbs-sec2/ft) 519.2-3 METHOD .519.2