基于迟滞行为的2D-SiC/SiC复合材料组份力学性能分析

基于剪滞理论, 建立了单向纤维增强陶瓷基复合材料的加卸载理论模型, 分析了基体长碎块和短碎块对材料迟滞力学行为的不同影响. 通过拉伸循环加卸载试验, 获得了2D-SiC/SiC 复合材料的迟滞应力—应变行为.依据材料基体损伤特点, 将试验结果代入长碎块对应理论推导结果, 计算得到了4 个表征材料组份性能的参数:基体开裂应力为90 MPa, 热残余应力为19 MPa, 界面脱粘能为3.1 Jm2, 界面滑移力为74 MPa. 最后结合少量短碎块的存在对试验结果的影响, 定性分析了计算结果的偏差. 结果表明, 获得的材料组分性能参数具有较小的分散性, 并能够准确表征材料整体的力学行为. 

STUDY ON CONSTITUENT PROPERTIES OF A 2D-SiC/SiC COMPOSITE BY HYSTERESIS MEASURMENTS

Continuous fiber reinforced ceramic matrix composites (CMCs) have outstanding mechanical properties. It is considered as a potential refractory material applied in aerospace fields. Study on CMCs' constituent properties has significant importance to the design, manufacture and engineering applications. In this paper, a method was prepared for assessing constituent properties of composites from hysteresis loops. The method is straightforward experimentally and provides values of constituent parameters directly. In detail, a hysteresis model in one dimension was constructed by shear-lag theory. The diverse effects of long and short matrix fragments on hysteresis behaviors were studied. And the hysteresis behaviors of a 2D-SiC/SiC composite were gained from tensile test. Considering the actual process of matrix cracking, all SiC matrixs was assumed to crack into long fragment. Values of four constituent parameters were calculated out: matrix cracking stress as 90MPa, residual stress as 19MPa, interfacial debond energy as 3.1 J/m² and sliding stress as 74MPa. Considering the influence of the few short fragments, the accuracy of calculations is analyzed. The calculations show a good dispersion and characterize the mechanical properties of 2D-SiC/SiC composites well.