考虑基体开裂的陶瓷基复合材料应力-应变曲线模拟方法及验证  

Simulating and validating the stress-strain curve of the matrix cracking of ceramic matrix composite

作　　者：孙志刚[1] 苗艳[1] 宋迎东[1] 

机构地区：[1]南京航空航天大学能源与动力学院,南京210016

出　　处：《航空动力学报》2012年第9期2056-2062,共7页Journal of Aerospace Power

基　　金：国家重点基础研究发展计划;国家自然科学基金(51075204);航空科学基金(2009ZB52028);南京航空航天大学基本科研业务费专项科研项目(NS2010044;NZ2012106);博士点基金(20070287039)

摘　　要：提出了蒙特卡罗方法模拟陶瓷基复合材料基体随机开裂过程,采用剪滞模型描述了复合材料出现损伤时细观应力场,并推导得到了考虑基体开裂时复合材料拉伸应力-应变曲线计算公式.开展了室温环境下C/SiC复合材料的单轴拉伸试验,并将理论预测应力-应变曲线与试验结果进行对比.同时,采用该方法对SiC/CAS,SiC/Si3N4复合材料应力-应变曲线进行了模拟,并与国外提供的相关试验数据进行比较,发现两者吻合得较好,从而证实了蒙特卡罗法可有效地模拟考虑基体随机开裂过程的陶瓷基复合材料应力-应变曲线.此外,还分析了Weibull模量、残余热应力和初始开裂应力对应力-应变曲线的影响.研究表明:Weibull模量越大,应力-应变曲线非线性越明显;热残余应力越大,应力-应变曲线偏转越早,非线性越明显;初始开裂应力与Weibull模量对应力-应变曲线影响规律相似.The matrix random cracking of ceramic matrix composite was simulated by Montel Carlo model.The shear-lag model was used to analyze the micro-stress field of the damaged composites,and the formula of the stress-strain behavior was derived.The uniaxial tensile experiment of unidirectional-C/SiC composites at ambient temperature has been performed,and the simulated stress-strain curve was compared to the experimental data.The tensile stress-strain curves of SiC/CAS and SiC/Si3N4 composites were simulated,which agreed well with the related experimental results.Besides,infuence of the model parameters on stress-strain curve was analyzed.Research shows that the higher the Weibull modulus,the more evident the non-linear phenomenon;the higher the thermal residual stress,the earlier the non-linear phenomenon appears;the effect of the minimum cracking stress on the stress-strain is similar to the effect of the Weibull modulus;the Monte Carlo model can simulate the stress-strain curve of ceramic matrix composites efficiently.

关 键 词：蒙特卡罗 基体 随机开裂 应力-应变曲线 陶瓷基复合材料 

分 类 号：V214[航空宇航科学与技术—航空宇航推进理论与工程] TB332[一般工业技术—材料科学与工程]