热应力下双材料表面裂纹的应力强度因子

Stress intensity factor of surface crack for bimaterial under thermal stress

使用交互积分法分别计算了单一材料和双材料表面裂纹受远场拉应力作用时的应力强度因子,并与GOSZ等人的经典结果对比,验证了数值方法的可行性;进而应用此方法求解热应力作用时的情况,分别计算了不同裂纹形状,不同模型厚度以及不同弹性模量比情况下的应力强度因子,数值结果表明:裂纹的长短轴比a/c越小,热应力对应力强度因子的影响就越大;当模型厚度和裂纹深度接近时,热应力对KII有较大的影响,而模型厚度远大于裂纹深度时,这种影响就可以忽略不计;材料匹配程度越好,热应力对应力强度因子的影响越小,反之这种影响就很大.

A numerical method called interaction integral method was used to compute the stress intensity factor（SIF） of surface crack in homogeneous materials and bimaterials subjected to remote tension.The result agrees with the classical solution obtained by GOSZ well.Then this method was applied to solve the stress intensity factor of surface crack for bimaterial subjected to thermal stress.The influence of crack shape,model thickness,crack depth and Young＇s modulus on the SIFs was analyzed in detail.The SIF changed intensely when the a/c was small.The KII was significantly influenced by the model depth that was close to the crack depth,whereas it changed negligibly when the model depth was large enough.In addition,the influence of thermal stress on SIF was negligible if the properties of the bi-material matched each other well,and vice versa.