基于子模型的复合材料主承力混杂连接结构失效分析

Taking the lower panel stringer joint structure in the composite wing root of civil aircraft as the research object, a three-dimensional sub-model of a single-bolt joint considering material damage was established, and the joint failure mechanism and the nonlinear load-deformation relationship were analyzed using the sub-model. After calculating the nonlinear fastener load distribution, the global finite element model was used to estimate the failure load while taking the nonlinear joint stiffness into account. By using the above method, the problems such as low computational efficiency and poor convergence caused by direct establishment of a full-size 3D model and considering damage are solved. The test confirms the efficacy of the suggested approach since the results indicate that the predicted failure mode is the simultaneous shear fracture of single-side multi-row fasteners, which is consistent with the test failure mode, and the predicted failure load is 93.6% of the test failure load. In contrast, the failure load predicted by the model with linear joint stiffness is 81.9% of the test failure load, and the predicted failure mode is the failure of the first row fasteners, which is obviously different from the test results.