406 



scheme: 



Rupture: ^m "^ c » 

 No Rupture: £ < t , 



(57) 



where u is the critical rupture strain and is an intrinsic property 

 of the material. Combination of ^qs. (54) and (56) with the critical 

 condition for rupture, (-^ = C^, leads to the result 



giving the conditions under viiich ruptiore just occurs. Introducing fc , 

 the energy per unit weight of explosive, and '£, the weight of explosive, 

 Eq. (58) may be rewritten: 





(59) 



It is of interest to determine the minimuci weight W of a 

 spherical charge of a given explosive causing rupture when eiqjloding 

 in contact with a plate of thickness a and yield stress o— , In this 

 case the distance R between the middle surface of the plate and the 

 charge center is equated to the sum of the charge radius and one-half 

 of the plate thickness with the result: 



R =^-MJ\ + l/2a^, (60) 



where yOg is the density of loading of the explosive. Substituting Eq. 

 (60) into Eq. (59) the desired relation between a,-,, v-q, and W is obtained 

 in the form 



87 



