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采用分离式Hopkinson拉杆装置和电子万能试验机研究了二维C/SiC复合材料在4种应变率(0.001、0.010、90.000和350.000s~(-1))下的拉伸力学性能,计算并验证了动态试验中的应力平衡状态;采用SEM分析了复合材料在不同应变率下的破坏断口和失效机制;建立了复合材料包含损伤和应变率相关的本构方程。结果表明:二维C/SiC复合材料的应力-应变曲线都表现出非线性的特征。随着应变率的增加,二维C/SiC复合材料的拉伸强度从204MPa增加到270MPa,增加了33%,这表明复合材料的拉伸强度具有较强的应变率敏感性。复合材料在准静态和动态加载下表现出不同的破坏模式是由材料内部界面行为的应变率效应造成的。
Tensile mechanical properties of two-dimensional C / SiC composites at four strain rates (0.001, 0.010, 90.000 and 350.000 s -1) were investigated using a split Hopkinson rod system and an electronic universal testing machine. The stress equilibrium state in the dynamic test was analyzed. The failure mechanism and failure mechanism of the composites at different strain rates were analyzed by SEM. The constitutive equation was established for the composites including damage and strain rate. The results show that the stress-strain curves of two-dimensional C / SiC composites show non-linear characteristics. With the increase of strain rate, the tensile strength of two-dimensional C / SiC composites increases from 204 MPa to 270 MPa, an increase of 33%, indicating that the tensile strength of the composites has strong strain rate sensitivity. The different modes of failure of the composites under quasi-static and dynamic loading are caused by the strain-rate effect of the interfacial behavior of the material.