Progressive failure analysis of composite pi joint with 3D FE modeling

Aimed at the complex failure modes of composite pi joint, the material elastic modulus degradation method was applied to simulate the progressive failure procedure. A three-dimensional finite element model of one type composite pi joint was established based on the commercial finite element software Abaqus. Two progressive failure analysis subroutines considering both the composite laminates and adhesive failures were developed within Abaqus/Standard. One of them is based on Hashin three-dimensional failure criteria and Ye-delamination criterion to distinguish five failure modes of composite laminates: fiber breakage, fiber buckling, matrix tensile cracking, matrix compression, and delamination failure. The other is based on Tsai-Wu criterion to discriminate the composite failure. Additionally, an elastic-perfectly plastic material model was applied in the subroutines to simulate the adhesive failure. The established pi joint model was analyzed under given increasing tensile loads. The numerical results show that the proposed method is effective in predicting initial failure position, initial failure load, final failure load and failure modes for the present composite pi joint.