双向等轴拉伸载荷下二维编织陶瓷基复合材料的应力-应变行为预测

Prediction of Stress-strain Behavior in 2D Weave Ceramic Matrix Composite under 1∶1 Planar Biaxial Tensile Loading

将二维编织结构简化为(0°/90°)s正交铺层结构。采用含损伤变量的剪滞分析理论,解得双向等轴拉伸载荷下,0°层和90°层开裂后各层的应力分布;基于随机基体裂纹演化理论,随机纤维损伤和最终失效理论,确定了0°层和90°层沿纤维方向的应力-应变关系,以及切线拉伸模量与施加载荷之间的关系;然后,将切线拉伸模量代入正交铺层结构的剪滞分析中,进而预测出二维编织陶瓷基复合材料在双向等轴拉伸载荷下的应力-应变关系。预测结果表明:在双向等轴拉伸载荷下,二维编织陶瓷基复合材料的横向和纵向应力-应变曲线基本相同,与单向加载时的应力-应变曲线相近。

For the purpose of predicting stress-strain behavior under the 1：1 planar biaxial tensile loading condition, 2D weave structure was simplified as crossply structure. A simplified shear lag analysis using a progressive scheme was proposed for the crossply structure. Closed form solution for stress distributions and traverse crack density of damaged plies as well as the entire laminate could be obtained as a function of the applied load. Based on stochastic matrix crack evolution and stochastic fiber damage, stress- strain behavior and tangent tensile modulus related to applied load in each ply were obtained. And then substituting tangent tensile modulus into the simplified shear lag analysis of crossply structure, stress-strain curve of 2D weave ceramic matrix composite was drawn. Predicted results show that longitudinal and transverse stress-strain curves are almost the same. Predicted results also show that stress-strain curves under the 1：1 planar biaxial tensile loading and under the uniaxial tensile loading are very close.