In this paper, a 3D finite element model is established in ABAQUS/Explicit based on a modified progressive damage model to study the dynamic mechanical response and damage development in cross-ply composite laminates subjected to low-velocity impact. The 3D Hashin criterion and the damage evolution model with the through-thickness normal stress component σ 33 are applied to predict the intra-laminar damage initiation and evolution. The cohesive elements with the bilinear traction-separation relationship are inserted between layers to predict the inter-laminar delamination induced by impact loading. A user-material subroutine VUMAT involving the modified progressive damage model of intra-laminar and inter-laminar damage is coded and implemented in the finite element package ABAQUS/Explicit. The numerical results of three different impact energies (7.35, 11.03 and 14.70 J) are analyzed by the impact force-time, force-displacement and energy-time histories curves as well as different damage modes. The respectable relationship between numerical simulation and experimental result indicates that the proposed modified method is more suitable for low-velocity impact on composite laminates under different impact energies than the previous method without σ 33. Moreover, the effects of S mt and S mc on global mechanical response and local damage predictions for laminates are discussed in detail. It can be concluded that both of the coefficients should be adopted between 0.93 and 0.96 when using this damage model to simulate composite laminates under low-velocity impact.

The dynamic mechanical responses and damage development of cross-ply composite laminates under repeated low-velocity impact are investigated through finite element simulations with ABAQUS/Explicit. A progressive damage model for laminates, consisting of the continuum damage model, the 3D Hashin failure criterion and the damage evolution model based on equivalent displacement, is integrated with the bilinear traction-separation relationship cohesive model to simulate the damage initiation, evolution and propagation behavior of different damage modes in composite laminates. Compared with the experimental results, the established finite element model was validated through the global mechanical response and damage distribution contous. Besides, a mesh refinement study was performed by using three different element sizes. The validated model was adopted to investigate the repeated impact behaviors of composite laminates under three different energies. The qualitative conclusions about the effects of repeated impact on global mechanical response were summarized by the changes of impact force, displacement, contact time and energy absorption. Moreover, the effects of repeated impact on the damage characteristics and expansions of matrix and delamination were discussed in detail.

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