Compressive mechanics and failure mechanism for uhmwpe fiber reinforced composite laminates under hygrothermal environment

Quasi-static and high strain rate compressive mechanics and failure behaviors of hygrothermal treated ultra-high molecular weight polyethylene (UHMWPE)/polyurethane composite were studied in this paper. Firstly, the UHMWPE composites were treated under hygrothermal environment for 12 days and 24 days. The out-of-plane compressions were then performed on the dry/wet state specimens at quasi-static states (0.001/s) and high strain rate states (1000-3000/s). The split Hopkinson pressure bar (SHPB) was adopted in the dynamic tests. Stress balance at both ends of the specimen was verified and waveform shapers were used to smooth and control the incident pulse. Failure modes of specimens conducted at quasi-static compression and dynamic compression were found to be different. Results show that the out-of-plane compressive stress of UHMWPE composites has strain rate sensitivity at high strain rate. The hygrothermal treatment improves the high strain rate peak stress while decreases the quasi-static compressive strength.