复合材料加筋板低速冲击损伤的数值模拟

建立了复合材料加筋板在横向低速冲击载荷作用下的渐进损伤有限元模型。该模型考虑了复合材料加筋板受低速冲击时的纤维断裂、基体开裂及分层脱粘等五种典型的损伤形式, 在层内采用应变描述的失效判据, 结合相应的材料性能退化方案, 通过编写VUMAT用户自定义子程序以实现相应损伤类型的判断和演化。在层间以及筋条与层板间加入界面元, 模拟层间区域的情况, 结合传统的应力失效判据和断裂力学中的能量释放率准则来判断分层损伤的起始和演化规律。通过对数值模拟结果与实验数据的比较, 验证了模型的合理性和有效性。同时探讨了不同位置、不同冲击能量以及含初始损伤(脱粘)等因素对复合材料加筋板低速冲击性能的影响。

Numerical simulation of low velocity impact damage on stiffened composite panels

A progressive damage finite element model was established for the analysis of stiffened composite panels under transversely low velocity impact. Five typical damage modes including fiber tensile failure, matrix crushing and delamination were considered in the model. Strain-based failure criteria coupled with corresponding stiffness degradation technologies were used to predict the type and evolution of intralaminar damage modes by VUMAT user-defined subroutine. Cohesive elements were adopted in interlaminar zones and zones between stiffener and laminates to simulate the initiation and evolution of delamination through stress-based failure criteria and facture-mechanics-based failure criterion. The reasonability and effectiveness were validated by the comparison between numerical simulation results and experimental data. Finally, the influence of impact position, impact energy and initial damage (delamination) on the low-velocity impact damage of stiffened composite panels was discussed in detail.