纤维失效对陶瓷基复合材料准静态加卸载迟滞回线的影响(英文)

采用双参数威布尔模型描述纤维强度分布,结合总体载荷承担准则确定基体裂纹平面处断裂纤维和完好纤维承担载荷。基于卸载/重新加载时纤维相对基体滑移损伤机理,确定了纤维轴向应力分布。采用断裂力学方法确定了界面脱粘长度、卸载界面反向滑移长度和重新加载新界面滑移长度,对比了不同峰值应力下考虑和未考虑纤维失效影响的迟滞回线,分析了纤维特征强度和纤维威布尔模量对纤维失效、迟滞回线形状和面积的影响,预测的迟滞回线与试验数据相吻合。

EFFECT OF FIBER FAILURE ON QUASI-STATIC UNLOADING/RELOADING HYSTERESIS LOOPS OF CERAMIC MATRIX COMPOSITES

The two-parameter Weibull model is used to describe the fiber strength distribution. The stress carried by the intact and fracture fibers on the matrix crack plane during unloading/reloading is determined based on the global load sharing criterion. The axial stress distribution of intact fibers upon unloading and reloading is determined based on the mechanisms of fiber sliding relative to matrix in the interface debonded region. The interface debonded length, unloading interface counter slip length, and reloading interface new slip length are obtained by the fracture mechanics approach. The hysteresis loops corresponding to different stresses considering fiber failure are compared with the cases without considering fiber failure. The effects of fiber characteristic strength and fiber Weibull modulus on the fiber failure, the shape, and the area of the hysteresis loops are analyzed. The predicted quasi-static unloading/reloading hysteresis loops agree well with experimental data.