一个双向载荷下弹塑性裂纹稳定扩展的分析方法

An Approach to Elasto-Plastic Stable Crack Propagation under Biaxial Loading

本文提出了一个用相对准则分析双向载荷下弹塑性裂纹稳定扩展的方法。首先,由单向载荷裂纹稳定扩展试验所得到的外载荷与裂纹扩展量的关系曲线进行模拟裂纹稳定扩展的“产生型”数值分析,得到有关参量与裂纹扩展的关系曲线,然后选择计算得到的参量值作为相对准则,再对双向载荷下裂纹稳定扩展问题进行“应用型”分析,最后得到双向载荷作用下外载荷与裂纹扩展量的关系。文中运用上述方法,分别选择裂纹张开角 COA 和 J 积分作为相对准则,对一个铝合金中心裂纹试件在双向载荷作用下的裂纹稳定扩展问题进行了分析。计算所得结果表明,运用此法分析双向载荷下的裂纹稳定扩展问题是可行的且双向载荷对裂纹的起裂载荷及整个稳定扩展过程都有影响,尤其在双向载荷比λ<0(λ=P_x/P_y)时,更为明显。

In this paper,a relative criterion method is presented for analysing the elastic plastic stable crack propagation under biaxial loading conditions.First,a “generation phase” analysis of stable crack propagation was performed according to the experimental results under uniaxial loading and the relations between some relevant parameters.Crack propagation was thus obtained.Secondly,the “application phase” analysis under biaxial loading was carried out by selecting the above paramete(?) values as a relative criterion.Finally,the relation between the applied load and crack propagation was obtained.Using the above method,an analysis of stable crack propagation under biaxial loading for a center-cracked specemen of alumimum alloy was performed by choosing COA and J-integral as relative criterions,respectively.The results obtained show that the effect of biaxial loading on both crack generation and the stable crack propagation must not be neglected.