力、热载荷作用下纤维在复合材料中的界面应力传递行为

Interfacial stress transfer behavior of single-fiber composite under the effect of mechanical and thermal loading

采用三维光弹性实验应力分析和有限元计算两种方法,在拉拔载荷和热残余应力联合作用下,对单丝拔出树脂基复合材料三维冻结切片界面剪应力进行了研究。实验结果和计算表明,在单纤维与基体界面的埋入端及埋入末端附近出现界面残余剪应力的极值;力、热载荷作用下纤维界面剪应力呈抛物线分布,单丝埋入端附近是应力的主要传递区域,最先达到危险应力,出现界面脱胶破坏,然后剪应力沿纤维埋入长度由纤维埋入端附近向埋入末端逐渐传递;界面热残余应力对界面剪应力的影响是使纤维埋入末端应力集中程度降低,使界面剪应力最大值增大。

The interfacial shear stress of a three dimensional freezing slice of single-fiber pullout resin matrix composites under the combined effect of pullout loading and thermal residual stress was studied using the three dimensional photo-elasticity and the finite element method. The results show that the value of the interfacial thermal residual stress reaches its peaks near the ends of the embedded fiber in the interface of the single-fiber and the matrix. The interfacial shear stress presents a parabolic distribution, and the transferring area mainly focuses on the region of the embedded top of the fiber where the stress reaches the critical point first, causing the debonding of the interface, and then the shear stress transfers along the embedded fiber. The effect of interracial thermal residual stress on the interfacial shear stress reduces the stress concentration near the end of the embedded fiber, making the maximum of the interfacial shear stress increase.