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为预测复合材料层合板的低速冲击特性,提出一种基于弹簧-质量模型的冲击分层响应模拟方法。首先根据假定的分层数量和分层面积计算分层前后的弯曲刚度与挠度变化,进而模拟出含分层过程的冲击头运动时间历程。然后,由冲击头的加速度计算接触力,并基于材料的弹-塑性接触定律计算出永久凹坑深度。随后,对共固化复合材料翼盒的壁板进行了低速冲击实验,冲击点分为3种类型:2个梁间蒙皮的中点位置、蒙皮与翼梁T型连接的胶接区边界和梁的正上方。接着,分析对比了不同冲击点的接触力、分层阈值力和凹坑深度的特点。最后,使用所提出的模型计算第1种冲击点的接触力、永久凹坑深度和吸收能量,并分析了矩形板长宽比对薄膜刚度及接触力的影响。结果表明:模拟的接触力与实测结果吻合良好,对永久凹坑深度和吸收能量的模拟精度也较高,所提模拟方法有效;随着长宽比的减小,薄膜刚度迅速增大,从而使接触力显著增大。
In order to predict the low-speed impact properties of the composite laminates, a spring-mass model based model for the impact stratification response is proposed. Firstly, the change of flexural rigidity and deflection before and after stratification is calculated according to the assumed number of stratification and stratification area, and then the impact time history of the impact head with stratification process is simulated. Then, the contact force is calculated from the acceleration of the impact head and the permanent pit depth is calculated based on the elastic-plastic contact law of the material. Subsequently, the low-velocity impact experiments were conducted on the panels of the composite wing box. The impact points were classified into three types: the mid-point position of the skin between the two beams, the boundary between the skin and the T-junction of the spar And just above the beam. Then, the characteristics of contact force, delamination threshold force and pit depth at different impact points are analyzed and compared. Finally, the proposed model was used to calculate the contact force, the permanent pit depth and the absorbed energy of the first impact point. The effect of the aspect ratio of the rectangular plate on the stiffness and contact force of the film was also analyzed. The results show that the simulated contact force is in good agreement with the measured results, and the simulation accuracy of the permanent pit depth and absorbed energy is also high. The simulation method is effective. As the aspect ratio decreases, the film stiffness increases rapidly So that contact force significantly increased.