铝合金裂纹扩展过程中裂纹前缘应力场的数值模拟

Numerical Simulation on Crack Front Stress Field in Process of Crack Propagation for Aluminum Alloy

在ABAQUS有限元平台上建立模型,模拟在一对拉应力作用下裂纹扩展过程中裂纹前缘应力场的演化情况。结果表明:在加载过程中,由于裂纹端点附近材料发生软化,应力反而下降,导致裂纹前缘应力重新分布。垂直于裂纹延长线上的应力的最大值不是在裂纹端点而是出现在裂纹延长线上,且离端点有一定距离处。裂纹前缘的等效塑性应变(PEEQ)随载荷的增大而急剧上升,但是沿裂纹线的方向又下降。这说明材料损伤发生于裂纹前缘很小区域内,这并未影响到其他区域。

On the platform of ABAQUS finite element model, the evolutions of the crack front stress field in the process of crack propagation under the effect of a pair of tensile stress were simulated. The results show that in the process of loading, the crack near the endpoint material softens, the stress drops instead, which can lead to the crack front stress redistribution. The maximum stress of S 11 in the crack doesn＇t appear on the crack tip but on the crack extension line, and is a certain distance from the endpoint. The crack front equivalent plastic strain （PEEQ） increases with the load increasing and then decreases along the crack line direction. It indicates that the material damage happens on the small area of the crack front, which can not affect the other area.