Shear stability test and strength prediction of composite laminates

The shear stability tests of composite laminates without damage and with impact damage were carried out. The post buckling behavior of composite laminates was measured in real time based on digital image correlation (DIC). The test results show that after the introduction of impact damage, the shear buckling waveform and buckling load of composite laminates do not change significantly, and the failure mode changes, the bearing capacity decreased by 9.69%. Then, based on the fracture surface failure theory, a progressive damage failure model of composite materials considering shear nonlinear effect was established, and the shear failure process of composite laminates was simulated. The softened inclusion method was used to simplify the impact damage, and the geometric boundary information of the damage area was directly written into the material model. There was no need to cut the impact damage area, so as to ensure the overall grid quality. Compared with the experimental results, it is found that the model considering shear nonlinearity has no obvious influence on the prediction of buckling load, and has a great influence on the prediction accuracy of post buckling capacity. The error without considering shear nonlinearity can reach more than 20%; The softened inclusion method can effectively simulate the impact damage. The predicted buckling load and failure load errors of composite laminates with impact damage are −3.17% and −1.27% respectively. © 2023 Beijing University of Aeronautics and Astronautics (BUAA). All rights reserved.