An enhanced elastoplastic damage coupled model for compression characteristics analysis of continuous fiber-reinforced thermoplastic composite stiffened panel

In this work, the elastoplastic behaviors, damage characteristics, and debonding forms of continuous fiber-reinforced thermoplastic (CFRTP) composite stiffened panel under uniaxial compression load have been stud-ied. The enhanced elastoplastic damage coupled model (EPDM) was established to model the mechanical properties of CFRTP composites which were based on generalized Hill yield criterion, the associated flow rules, the power hardening law, Chang-Chang failure criterion, and continuous damage mechanics (CDM). The forward Euler algorithm was implemented in Abaqus via user-defined subroutine VUMAT. A series of experiments including tensile, compression, and interlaminar shear tests of laminates were performed to validate the material model. Subsequently, the developed EPDM combined with cohesive zone model (CZM) was applied to simulate the nonlinear mechanical responses of CFRTP composite stiffened panel. Moreover, an axial compression test of CFRTP composite stiffened panel was also carried out, which confirmed that the simulation results were in agreement with the corresponding experimental results. Furthermore, based on the established finite element model, the buckling knockdown factor (KDF) and plastic region development of the CFRTP composite stiffened panel were also analyzed. Overall, the obtained results demonstrate the efficiency of the proposed EPDM for the compression characteristics analysis of the CFRTP composite structures.