Effect of stacking sequence on multi‐point low‐velocity impact and compression after impact damage mechanisms of UHMWPE composites

Composite materials are susceptible to low velocity impact, which is a very common phenomenon. A large number of studies have been conducted on the single‐point impact on their mechanical properties, but there is a lack of in‐depth exploration on the actual situation of multi‐point impact with a certain angle distribution of impact points. In this paper, three impact points with a certain angle distribution were set to carry out low‐velocity impact (LVI) sequentially, followed by compression after impact (CAI). Digital image correlation system (DIC) and X‐ray micro‐computed tomography techniques (micro‐CT) were used to analyze the mechanical response and failure mechanisms of the specimens. Experimental results demonstrated that the distribution of impact points will directly affect the overall mechanical properties of the material, and the mechanical properties are also sensitive to the stacking sequence. More importantly, it was also found that the boundary conditions have a great influence on the overall mechanical response, which makes the surrounding damage worse.