Mechanical Properties and Failure Analysis of UHMWPE Fiber Composite Laminates under Compressive Loading

To determine the mechanical properties and failure modes of ultra-high molecular weight polyethylene (UHMWPE) fiber composite laminates under static and dynamic compressive loading, a universal material testing machine (UTM) and a split Hopkinson pressure bar (SHPB) experimental system were used to obtain the stress-strain relationships of UHMWPE subjected to out-of-plane compression at different strain rate loading. After experiments, the microscopic failure morphology of the material was observed through scanning electron microscopy (SEM), then the failure mode of the material was analyzed. The results show that the UHMWPE fiber composite laminates performs a rate-independent behavior at low strain rates (6.7×10⁻³ s⁻¹ to 6.7×10⁻² s⁻¹); while a rate-dependent at high strain rates (2.05×10³ s⁻¹ to 5.27×10³ s⁻¹). The compression strength increases with the rising strain rate, and the dynamic enhancement factor gradually increases, with an obvious strain rate strengthening effect. Under static compression, the main damage mode of UHMWPE is the stretching and fracture of the fibers, while at dynamic situation, the main damage mode of the material is the longitudinal dislocation delamination.