Behavior of composite structures orientations towards their failure and damage

Abstract

In this paper, carbon/epoxy composites were employed as a potential candidate for spacecraft structural shielding along with the new concept of geometric configurations according to the threat severity to maximize the impactor energy absorption to improve performance. Carbon/epoxy composites of quasi-isotropic 16 layers [0/+/- 45/90](2s) were manufactured using an autoclave, and the specimens were exposed to a low Earth orbit environment, which produced an average total mass loss of 0.42%, mainly due to outgassing. Al2017-T4 spherical projectiles with a diameter of 5.56mm weight of 0.25g were used as the impactor in the velocity range of 1500 +/- 500m/s. Earlier experimentations showed the superiority of obliquity towards energy absorption for single bumpers. Double bumpers with one 45 degrees obliquity at 100mm standoff absorbed 14% more specific energy than double bumpers with one at 30 degrees; both of them were found to be superior to normal-normal bumpers by 40% and 30% on average, respectively. By CSCAN, it was also found that oblique impact on the first bumper resulted in less damage on the rear bumper and resulted in the superiority of the proposed geometric configurations, which enabled enhanced protection and designs according to threat severity.