Hypervelocity impact on carbon/epoxy composites in low Earth orbit environment

Abstract

This paper describes the hypervelocity impact phenomenon on the spacecraft composite bumper especially when the incidence angle is oblique in nature. Three different kinds of specimens namely Al6061-T6, carbon/epoxy non-aged and aged under low Earth orbit environment were manufactured, tested, and validated in this research. These composites were manufactured with 16 layers of CU125NS with the stacking sequence of [(0/+/- 45/90)(2)](s) using autoclave by adopting standard procedures. Afterwards, the specimens were exposed to LEO space environment with UV light, atomic Oxygen, high vacuum, and thermal cycling. The specimens were then impacted by Al2017-T4 spherical projectiles 5.56 mm in diameter and, 0.25 g in weight within the velocity range of 1000 +/- 100 m/s. Due to LEO environment exposure, a total mass loss of 0.42% was found in the composites along with degradation in other mechanical properties because of the synergistic effects of UV and AO. The specific energy absorption of the composites was found to be 7% greater than that of Al6061-T6. Secondly, with the increase of incidence angle obliquity, the energy absorption by the composites also increased exponentially. In the end, C-SCAN study was done to evaluate the impact surface and its failure. On the basis of these findings, oblique composite bumpers are suggested as effective spacecraft shielding.