Analysis Of Polymer Hypervelocity Impact Characteristics And Strain Rate Effect

It will be damaged or even disintegrated by the hypervelocity impact of space debris when a spacecraft is in orbit.Studies have shown that the strain rate during a hypervelocity collision can reach more than 10⁶s^-1.The study of the mechanical properties of materials at ultra-high strain rates has important engineering value for the anti-space debris damage and protection of spacecraft structures,and even the long-life and safe operation of spacecraft in orbit.In recent years,high-performance polymer fiber materials have been widely used in spacecraft space debris protection structures and other large-scale flexible structures.This article focuses on the strain rate effect of polymer fiber materials and the impact characteristics of fiber fabrics during hypervelocity impact.The specific work is as follows:The quasi-static tensile and dynamic tensile experiments are carried out using the material testing machine and Hopkinson bar,the strain rate effect of UHMWPE fiber bundles and the stress-strain relationship of UHMWPE fiber bundles under different strain rates is obtained.The results show that the strain rate effect of UHMWPE fiber bundles is significant,which is different from that of quasi-static tension.Compared with elongation,its modulus and strength under high strain rate are significantly increased.On the basis of experimental research,molecular dynamics simulation was used to study the strain rate effect of UHMWPE fiber bundles.A coarse-grained UHMWPE model was established to simulate the dynamic tensile performance of UHMWPE at high strain rates,and the correctness of the model was verified by experimental results.The influence of strain rate,temperature and molecular weight on its tensile properties was analyzed.On the basis of UHMWPE fiber material performance experimental research and molecular dynamics simulation,considering its strain rate effect,an SPH-FEM coupling model of fiber fabric hypervelocity impact was established,and the correctness of the model was verified by experimental results.On this basis,the analysis of the influence of fiber fabric structural parameters on its hypervelocity impact characteristics is obtained.