2D-C/SiC复合材料的高温非线性本构模型  

NONLINEAR CONSTITUTIVE MODEL FOR 2D-C/SiC COMPOSITES AT ELEVATED TEMPERATURES

作　　者：杨成鹏[1] 林江嵘 贾斐 王波[3] Yang Chengpeng;Lin Jiangrong;Jia Fei;Wang Bo(School of Mechanics,Civil Engineering and Architecture,Northwestern Polytechnical University,Xi’an 710072,China;School of Mechano-Electronic Engineering,Xidian University,Xi’an 710071,China;School of Aeronautics,Northwestern Polytechnical University,Xi’an 710072,China)

机构地区：[1]西北工业大学力学与土木建筑学院,西安710072 [2]西安电子科技大学机电工程学院,西安710071 [3]西北工业大学航空学院,西安710072

出　　处：《力学学报》2023年第8期1721-1731,共11页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金资助项目(12072274)。

摘　　要：高温各向异性非线性本构关系对陶瓷基复合材料热结构设计具有重要科学和工程意义.为了分析预测2D-C/SiC复合材料在高温平面应力下的应力-应变行为,基于损伤解耦表征方法,考虑材料的损伤耦合效应、非线性和正交各向异性,建立了热力耦合损伤本构模型的理论框架.基于应变分割法,考虑热失配应力、基体开裂、界面脱黏、纤维桥连对卸载模量和残余应变的影响,给出了材料的轴向拉伸和面内剪切应力-应变关系分析模型,并进行了初步试验验证.在材料基本性能表征的基础上,对2D-C/SiC复合材料在不同偏轴角度(15°,30°和45°)和不同环境温度(27℃,973℃,1273℃和1473℃)下的拉伸应力-应变行为进行了模拟预测.结果表明,2D-C/SiC复合材料的应变响应具有显著的温度相关性,随着温度的升高材料的非线性程度降低,而随着偏轴角度的增大材料的非线性增强,不同偏轴角度下材料的表观模量均随着温度的升高有增大趋势;所建立的理论模型可对2D-C/SiC复合材料的应力-应变行为进行合理预测,模拟曲线与试验值具有较好一致性.High-temperature anisotropic nonlinear constitutive relationship is of great scientific and engineering significance for thermal structure design of ceramic matrix composites.In order to analyze and predict the stress-strain behavior of 2D-C/SiC composites under plane stress state at elevated temperatures,a thermal-mechanical coupled damage constitutive model was developed based on the damage decoupling characterization method,considering the damage coupling effect and material nonlinearity and orthotropy.Meanwhile,by application of the strain segmentation method,and taking into consideration of the effects of thermal mismatch stress,matrix cracking,interface debonding and fiber bridging on the unloading modulus and residual strain,the analytical models of on-axis tension and in-plane shear stress-strain relationships of the material were presented,and preliminary experimental validation were performed.On the basis of basic property characterization,the tensile stress-strain behavior of 2D-C/Si C composites under different offaxis angles,i.e.,15°,30° and 45°,and at elevated ambient temperatures(27 ℃,973 ℃,1273 ℃ and 1473 ℃) were simulated and predicted.The results show that the strain response of 2D-C/SiC composites depends significantly on environmental temperature.The degree of material nonlinearity decreases with the increase of temperature,while it increases with the increase of off-axis angle.Meanwhile,the apparent modulus of the material tends to increase with the increase of temperature at different off-axis angles.Besides,the developed theoretical model can reasonably predict the stress-strain behavior of 2D-C/SiC composites,and the simulated curves are in good agreement with the experimental data.

关 键 词：陶瓷基复合材料 正交各向异性 本构模型 损伤耦合 高温性能 

分 类 号：O34[理学—固体力学] TB332[理学—力学]