平纹编织复合材料层板高速冲击损伤机理研究

根据碳纤维平纹编织复合材料层板在高速冲击下的断裂形貌特征,基于能量守恒原理构建层板的能量解析模型。模型考虑弹体动能被层合板的剪切破坏、拉伸断裂、压缩变形、分层损伤以及冲击区运动等损伤模式吸收,最终得到常微分形式的能量平衡方程。方程的几何参数中剪切充塞孔深度由试验弹道极限速度及理论求解得到,裂纹长度和分层损伤区域通过弹道冲击试验测量获得。在验证模型准确性的基础上,研究表明层合板在中速冲击时纤维拉伸断裂损伤吸收最多的能量,而高速冲击时压缩变形成为主要的吸能方式。在整个冲击过程中,较大的分层损伤区域使得基体的能量吸收作用不可忽视。层合板在平头弹冲击下与圆头弹相比吸收了更多的能量。

STUDY ON DAMAGE MECHANISM OF PLAIN WEAVE COMPOSITE UNDER HIGH VELOCITY IMPACT

According to the fracture morphology of the plain weave carbon laminate,an analytical energy model was developed based on energy conservation law.The model considered that the kinetic energy of the projectile was absorbed by the laminate through shear failure,tensile fracture,compression deformation,delamination and moving in the crushed area during penetration.The influence of strain rate of the composite was taken into account.The depth of shear plugging was obtained by ballistic limit velocity in experiment and theory.Meanwhile,the crack length and the damage area of delamination were measured in impact experiment.The experiment for carbon weave composite laminate was conducted under flat and hemispheric projectile to obtain the ballistic limit velocity.Based on the validated model,further studies show that most energy is absorbed by tensile fracture of back surface under medium velocity,while compression deformation becomes the main absorbing mechanism under high velocity.The influence of delamination in energy absorption should be considered due to the large damage area.Meanwhile,more energy is absorbed by flat projectile than hemispherical projectile.