基于泛形理论的裂纹扩展路径模拟

The universal shape characteristics of the material fracture surface are caused by the internal inhomogeneity of the material. In this paper, using the random samples of elastic modulus measured by nanoindentation experiments, the Weibull statistical distribution parameters representing the inhomogeneous characteristics of the material are obtained; the crack propagation process of the HT250 specimen with cracks is numerically simulated based on the extended finite element method, and on this basis, the universal shape complexity of the crack propagation path is calculated, and the simulation results are in good agreement with the experimental results; the influence of different degrees of homogeneity of the aluminum alloy 7075 on the crack propagation of the inhomogeneous model is analyzed. The research results show that the mode I crack propagation path of gray cast iron has universal shape characteristics, and the universal shape complexity of the crack depends on the inhomogeneity of the material and has a negative correlation. This research method is also applicable to the crack propagation analysis of other materials with a single-valued stress-strain relationship.

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.