Study On Hypervelocity Impact On Flexible Composite Materials

With the development of human space activities, the population of space debris is growing rapidly. The threat to aritficial spacecraft is gradually increasing. The debris less than 1cm can only be shielded using shielding structure. Flexible composite material could be easily folded. Thus, a larger area of the multi-layered debris shield would be emitted with a smaller launch volume. It can improve impact protection efficiency and the area of protection zone definitely. In this paper, the performance of flexible composites against hypervelocity impact was studied.Firstly, Kevlar textile and Kevlar fiber reinforced polymer are selected according to the folding resistance property of fiber materials. Flexible composite protective bumper is prepared using the material mentioned above. The bumper made of traditional rigid material for aluminum alloy was used to conduct a comparison test to flexible composite materials. By analysing the damage morphology of the bumper, the fragmentation degree of the projectile and the damage degree of the check plate after the hypervelocity impact test. The shielding performance of the flexible composite was evaluated at last. The results show that flexible composite material is akin to aluminum alloy shield under hypervelocity impact, but flexible composites could be folding emission.The hypervelocity impact tests were conducted on Kevlar textile and Kevlar fiber reinforced polymer. The influence of the thickness of the material is obtained. The results show that as the increase of the thickness of the shield, the hypervelocity impact protection performance of the shield is improved. The effect of epoxy resin matrix on the failure behavior of the shield and the performance of hypervelocity impact protection are obtained. The results show that the proper amount of epoxy resin can improve the protective performance of unit mass. This is due to the epoxy resin fixxing the position of yarn on the textile. If the amount of epoxy resin continues to improve, the shielding performance improves a little. But the mass increased significantly. So, the shielding efficiency of composite material decreased.Secondly, multi-layered shielding structure of flexible composite materials were tested in hypervelocity impact experiment. The aluminum alloy bumper and carbon fiber reinforced polymer were used as reference material. The damage of bumper and projectile were analysed. By comparison, evaluation of the shielding performance of the multi-layered structure were made between the flexible composite material and the traditional material.Based on the hypervelocity impact test, the numerical simulation and analysis of hypervelocity impact to analyse the behavior of flexible composite material were carried out. The hypervelocity impact analysis model of flexible composites is established, and the validity and correctness of the model are verified by the test results. By applying the analytical model, the hypervelocity impact on bumper made of Kevlar fibre reinforced polymer with different thickness was numerically simulated. The damage of the shielding structure after impact and the fragmentation of the projectile and the residual kinetic energy of debris were studied. The relationship between protective shield thickness and protective performance is analyzed.The results show that as the thickness of the bumper increasing, the hypervelocity impact shielding performance of the structure improves. When the bumper thickness is less than 2.6mm, the shielding performance is more significant with the increase of thickness. The impact behavior of the projectile with different velocity is analysed. The kinetic energy absorption rate of the impact at different speeds was analyzed. The shielding performance of the bumper against projectiles with different velocity are obtained.The impact on multi-layered shielding structure made of flexible composite material is simulated. We obtain the shielding performance. The results show that the multi-layered shielding structure made of flexible materials have better performance when the velocity of impact is above 4.5km/s or below 1.5km/s.