SiC 纤维增强复合材料基体裂纹偏移机理的有限元分析

运用基于能量的裂纹偏移准则, 分别建立了两相和三相复合材料基体裂纹偏移/ 穿透的轴对称有限元模型, 考察了纤维体积分数、描述材料特性弹性失配的Dundurs 参数α和相对裂纹扩展长度a_d / a_p 对相对能量释放率Gd / Gp 的影响。将两相复合材料的有限元结果与He 等人的结果进行对比, 进一步考察了三相复合材料界面层厚度和Dundurs 参数α₁ 和α₂ 对G_d / G_p 的影响。分别将碳涂层SiC 纤维增强复合材料SiC/ C/ Ti-6A1-4V 和碳涂层陶瓷基增强复合材料SiC/ C/ SiC 运用于有限元分析中, 结果表明, 所建立的模型能够准确地预测和比较基体裂纹偏移的机理。 

Finite element analysis of matrix crack deflection mechanisms in f iber-reinforced composites

The axisymmet ric finite element models of the mat rix crack deflection/ penet ration for two -phase andthree-phase composites were established respectively by applying the energy-based crack deflection criterion. Theeffects of the fiber volume f raction , the Dundurs parameter αdescribing the elastic mismatch between material properties , and the relative crack growth length ad / ap on the relative energy release rate ratio Gd / Gp were investigated.The FEA result s were compared with those obtained by He for two-phase composites , and the effect s of the interphase thickness , Dundurs parametersα1 andα2 on Gd / Gp were further studied for three-phase composites. The SiCfiber-reinforced composite SiC/ C/ Ti-6Al-4V and ceramic composite SiC/ C/ SiC coated with cabon were analyzed bythe FEA respectively , and the result s show that the models can accurately predict and compare the mat rix crackdeflection mechanisms.