A Comparison of the Classical and a Modern Theory of Detonation

A q u i t e complete exposi t ion of what has been ca l l ed the c l a s s i c a l theory of detonat ion i s given i n t he S c i e n t i f i c American of May 1987 by W.C. Davis. However, Davis s t a t e s i n h i s repor t t h a t , "In s p i t e of t h e v a r i e t y of modern app l i ca t ions of explosives, detonat ion science has no t ye t reached maturi ty . . .," and, "Sc ien t i s t s who study explos ions a r e spurred on by being cons tan t ly reminded t h a t t h e cur ren t detonat ion theory i s incomplete. " I n t h i s paper a comparison i s made between t h e c l a s s i c a l theory as exppunded by Davis and a more modern theory based on the concepts t h a t : ( 1 ) The energy i n t h e very narrow shock o r detonat ion f r o n t i S high1 y nonergodi c , and thermal equilibrium, p a r t i c u l a r l y between t h e t r a n s l a t i o n a l and v ib ra t iona l energy modes, does not e x i s t i n t he f r o n t ; ( 2 ) No r e a l i s t i c temperature can be ascr ibed t o t h i s very narrow zone; and ( 3 ) A physical regul a t o r which cons t ra ins shock and detonat ion v e l o c i t i e s i s d i r e c t l y r e l a t e d t o t he v ib ra to ry v e l o c i t i e s of t h e atoms of t h e shocked mater ia l s . The paper includes a sho r t h i s t o r i c a l summary, a s t a t e ment of some c r u c i a l def ic ienc ies i n t h e c l a s s i c a l theory, and it contains t h e presenta t ion and discussion o f a number o f experiments and mathematical arguments favoring t h e a l t e r na t ive theory. Among these a r e experimental observat ions made i n t h e 1960s and 1970s and continuing t o t h e present . Proposa l s of tribochemical o r mechanical bond f r a c t u r e i n shock f r o n t s i n explosives were made a s e a r l y a s 1938, and they appeared occasional ly i n l a t e r years , but they were o f t e n ignored. F ina l ly , r e s u l t s from more recent experiments and ca l cu la t ions a r e summarized, which appear t o support fo rce fu l ly t h e a l t e r n a t i v e theory. Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jp4:1995419 JOURNAL DE PHYSIQUE IV