针刺陶瓷基复合材料损伤本构模型及构件应力分析

A damage constitutive model for needled CMCs composites and stress analysis of components

基于连续介质损伤力学方法提出了适用于针刺陶瓷基复合材料的各向异性损伤本构模型.该模型考虑了拉伸与剪切损伤的影响.通过试验得到了材料的拉伸和剪切的应力-应变曲线,采用曲线拟合获得了本构模型的参数.应用用户子程序技术将本构模型写入商用有限元软件,计算所得拉伸和剪切的应力-应变曲线与试验曲线比较吻合,最大误差分别为5.62%和1.47%.使用该损伤本构模型及弹性模型计算了航空发动机尾喷管调节片在气动和温度载荷下的力学响应,两者计算所得应力分布相似,但损伤本构模型计算值明显小于弹性模型计算值.

An anisotropic damage constitutive model for needled ceramic matrix composites was proposed based on continuum damage mechanics.The effects of both tensile damage and shear damage were considered in the model.The stress-strain curves of the material were obtained by tensile and shear tests and the parameters of the constitutive model obtained by curving-fitting.Then the model was written into commercial finite element software by user subroutine.Both calculated tensile and shear curves agreed with the test curves,and the maximum errors were 5.62%and 1.47%respectively.With both damage constitutive model and elastic model,an adjustment sheet of an aero-engine exhaust nozzle was calculated to analyze the mechanical response under complex aerodynamic load and temperature load.Thestress distributions calculated by the two models were similar,but the value of damage constitutive model was obviously lower than that of the elastic model.