Development of a Radio-Frequency Transparent Energy-Absorbing Structural Element.
Ronald H. Smith · NASA Technical Reports Server (NASA) · 1965
An experimental i n v e s t i g a t i o n has been conducted t o develop highly e f f i c i e n t energydbsorbing s t r u c t u r a l elements f r o m radi-f requency transparent materials.The materials were evaluated using two types of energy absorption processesj t h e fragmenting tube and t h e crushing of honeycomb and foamed materials.P l a s t i c reinf'orced glass f a b r i c tubes, employed i n t h e fragmenting tube process, yielded s p e c i f i c energies of 28,400 a.nd 12,300 f t -l b / l b f o r f a b r i c o r i e n t a t i o n i n t h e l o n g i t u d i n a l and b o p d i p e c t i o n s respectively.a value of s p e c i f i c energy of 14,400 ft-lb/lb f o r a 3/16 inch c e l l s i z e , 9.0 l b / f t The crushing of nylon-phenolic honeycomb yielded 3 density, and with a usable stroke of 80$ of i n i t i a l length.Radio frequency transmission l o s s e s were well within acceptable l i m i t s f o r t h e s p e c i f i e d 100 t o 2000 megacycle frequency range investigated.iiiFOREWORD . .