EMP Coupling to a Composite Aircraft

In t h i s p a p e r , r e s u l t s a r e p r e s e n t e d f o r n u c l e a r EMP c o u p l i n g t o an Advanced D e s ig n C om posi te A i r c r a f t (ADCA). The ADCA i s a c o n c e p t u a l a i r c r a f t w hose s k i n i s f a b r i c a ­ t e d o u t o f s i g n i f i c a n t p o r t i o n s o f g r a p h i t e e p oxy compo­ s i t e m a t e r i a l . Numer ical r e s u l t s a r e p r e s e n t e d f o r in d uc e d s u r f a c e c u r r e n t s and c h a r g e s ( e x t e r n a l c o u p l i n g ) and f o r s k i n d i f f u s i o n i n d u c e d c u r r e n t s and v o l t a g e s on t y p i c a l c a b l e runs i n s i d e t h e a i r c r a f t ( i n t e r n a l c o u ­ p l i n g ) . When t h e s e i n t e r n a l c o u p l i n g r e s u l t s a r e com­ pared t o t h o s e w h ich have been e x p e r i m e n t a l l y o b s e r v e d on m e t a l l i c a i r c r a f t , ( f o r w h ich s k i n d i f f u s i o n i s n o t i m p o r t a n t ) , one c o n c l u d e s t h a t t h e s k i n d i f f u s i o n in d uc e d l e v e l s a r e u s u a l l y s m a l l e r than t h o s e c a u s e d by a p e r t u r e s . How ever , t h e a v a i l a b l e power in t h e d i f f u s i o n in d uc e d t r a n s i e n t s i s s u f f i c i e n t by i t s e l f t o p o s s i b l y c a u s e d e v i c e damage o r c i r c u i t u p s e t . C a l c u l a t i o n s a r e a l s o done w i t h a h a r d e n in g f i x w hich c o n s i s t s o f a 6 m i l t h i c k aluminum f l a m e s p r a y c o a t i n g o v e r t h e e n t i r e a i r ­ c r a f t . T h i s f i x p r o v i d e s more than 40 dB a t t e n u a t i o n and t h e r e b y r e d u c e s t h e d i f f u s i o n i n d u c e d t r a n s i e n t s t o a s a f e l e v e l .