3D FEM analysis of the interlaminar reinforcement of short fibers

Toughening from interlaminar short fibers is one of the effective ways of interlaminar toughening in composite laminates. In order to study the effects of interlaminar short fibers on the delamination growth in composite laminates，the delamination growth in composite laminates with interlaminar short fibers was studied by 3D geometrically nonlinear and contact FEM. The FEM was improved with the virtual crack closure technique to calculate the energy release rate，and the current fracture criterion in mixed mode was used as the criterion for crack propagation. The crack propagation was simulated by node coupling/partition and the technology of element living and death. The effect of interlaminar short fibers was simulated by spring elements，and the bridging force of short fibers was modified by changing the spring stiffness. The GAP element method was used to deal with contact problems. The influence of interlaminar bridging stress on delamination front stresses，displacement and its growth was studied. Compared with delamination growth in composite panels without interlaminar short fibers，the results show that interlaminar short fibers can effectively reduce the delamination growth and enhance the interlaminar toughness.