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分别应用裂缝尖端应力场Westergaader解和Muskhelishvil解,推导了裂缝尖端微裂区轮廓线及特征尺寸的表达式;并根据幂指数描述的应变软化模型,给出了考虑应力松弛影响的断裂过程区(FPZ)总长及等效FPZ长度的解析表达式,探讨了三种脆性破坏强度准则及材料参数对FPZ尺寸的影响。分析结果表明:由莫尔强度准则及最大拉应变准则确定的FPZ轮廓均随拉压强度比和泊松比的减小而逐渐增大,并趋近于由最大拉应力准则确定的FPZ边界;由局部解得到的FPZ尺寸均比全场解小,且仅在应力水平较小、试件很大时适用。
Based on the stress softening model and the stress softening model described in the paper, the fracture process zone considering the influence of stress relaxation is given (Westergaader and Muskhelishvil solutions, respectively) FPZ) and the equivalent FPZ length were discussed. The influence of three kinds of brittle failure strength criteria and material parameters on the FPZ size were discussed. The results show that the FPZ profile determined by the Moiré criterion and the maximum tensile strain criterion both increase with the decrease of tensile strength and compressive strength and Poisson’s ratio and close to the FPZ boundary defined by the maximum tensile stress criterion. The FPZ size obtained by the local solution is smaller than that of the whole field, and only applies when the stress level is small and the specimen is very large.