压力敏感性弹塑性材料平面应力条件下起始扩展裂纹尖端的渐近场

Asymptotic Crack-Tip Fields for a Crack before Growing in Pressure Sensitive Elastic-Plastic Materials

采用一个能描述材料压力敏感性和SD效应的抛物型屈服准则,运用正交流动法则给出了材料的本构方程。在平面应力条件下,得出了裂纹尖端弹塑性应力场的基本解。在不同受力状态下(表现在采用不同的塑性混合因子),给出裂纹尖端应力场解的构造。讨论了材料参数对裂纹尖端应力场分布的影响。在自相似假设下讨论了应变的奇异性。结果表明,对于纯I型裂纹,在较低的拉伸应力作用下裂纹即开始起裂,而对于纯Ⅱ型裂纹,SD效应增强了材料的抗剪性能。

Based on the parabolic yield criterion which can describe pressure sensitive and SD effect of materials,the material constitutive equation was given by orthogonal flow rule.In the plane stress condition,a basic solution in elastic-plastic crack tip field was given.In different stress conditions（manifested in the different plastic mixture factors）,the different structures of solutions in the crack-tip were given.The different parameters in crack-tip stress field were discussed.The singularity of strain was discussed under the assumption of self-similarity.The results show the crack began to crack under the low tensile stress for the pure mode I and SD effect increases the properties of shear for the material for the pure mode Ⅱ.