Shock Transmission from Explosive to Metal Plate

Detonation, Shock Transmission from Explosive to Metal Plate. Accdg to Cook (Ref 3, p 1H) R.W. Goranson is credited with suggesting that it is possible to determine the p(x), W(x) and p(x) distribution in the detonation wave by studying the characteristics of the shock wave transmitted from the explosive into a thin metal plate in shock loading of the plate by a detonation wave. In this theory, when a plane detonation wave strikes a metal plate at normal incidence, a shock wave is transmitted into the plate and another is reflected back into the incident wave such. as to give a pressure-distance profile like that illustrated in Fig 5.17 [reproduced by Cook from the paper of Walsh Christian (Ref 1)]. 

The transmitted wave has a shock velocity Dm and a particle velocity Wm related thru conservation laws to velocity D and particle velocity W in the explosive. Upon reaching the free surface of the metal the shock is reflected as a rarefaction wave and the free surface acquires a velocity Vj of approx twice Wm. Hence, the measurement of Vj and gives a means of determining Wffl and pressure of shock p thru the equations  

PlmDf taken, in approximation, as equal to p D, the following equation may be deduced  

Here subscript 1 refers to original explosive subscript m refers to the transmitted wave, r to the reflected wave and no subscript applies to the incident wave. In the steady state D is constant, which permits one to measure W(x) directly thru the above equations. Also the ratio p /p may be obtd from a relation given by iSeal2 (Ref 2), from which equation 5.25 is obtained  

This equation makes possible the detn of C-J pressure p2 by extrapolation to zero-plate thickuess in cases where reaction-zone length aD is negligible. Deal assumed, furthermore, that this extrapolation should give p2 even where a0 is appreciable by an e xtrapolation which ignores the spike (Ref 3, pp 111-14) 

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Figure 5.17. Shock transmission from explosive to metal plate (after Walsh and Christian)...

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