基于泛形理论的裂纹扩展路径模拟

Simulation of Crack Growth Path Based on the Ubiquitiform Theory

材料断裂面的泛形特征是由于材料内部不均匀造成的.本文利用纳米压痕实验测得的弹性模量随机样本,得到了表示材料非均匀特性的Weibull统计分布参数;对含裂纹的HT250试件的裂纹扩展过程进行了基于扩展有限元法的数值模拟,在此结果上计算了裂纹扩展路径的泛形复杂度,模拟结果与试验结果吻合较好;分析了铝合金7075不同均质度对非均匀模型裂纹扩展的影响.研究结果表明,灰口铸铁的Ⅰ型裂纹扩展路径具有泛形特征,裂纹的泛形复杂度依赖于材料的非均匀性且呈负相关关系.该研究方法也适用于其他应力应变呈单值关系材料的裂纹扩展分析.

In this paper,the random samples of elastic modulus measured by nanoindentation experiment are used to obtain the Weibull statistical distribution parameters,which represent the non-uniform characteristics of materials.The crack growth process of the cracked HT250 specimen is simulated by the finite element method,and the ubiquitiformal complexity of crack growth path is calculated.The numerical results coincide well with the experimental results.The effects of different homogeneity on the non-uniform model cracks of aluminium alloy 7075 are analyzed.The results show that the mode-I crack growth path of gray cast iron is ubiquitiformal feature,and the ubiquitiformal complexity of material crack depends on its inhomogeneity and has a negative correlation with it.This method is also suitable for crack growth analysis of other materials with monotonic stress-strain relationship.