LC4-M材料复合型韧断主要影响因素的分析

The Analysis of Effect Factor on Mixed Mode Fracture of LC4-M Material

通过分析LC4 M铝合金材料在不同复合比载荷下的断裂试验结果 ,参照常规断裂现象 ,修正了一般断裂试验中认定裂纹启裂方向的方法 ,结合不同复合比下裂尖附近应力三维、主应力方向的计算分析 ,得到 :在裂端的钝化变形区域、应力三维度的极大值处 ,对应于裂纹的启裂位置 ,即使在高韧性材料中发生剪切断裂的情况下也是如此 ;裂纹的启裂方向在拉伸断裂时与启裂点最大拉应力方向有关 ,在剪切断裂时与启裂点最大剪应力方向有关 。

Refer to the results of macroscopic analysis for conventional fracture of sever al materials and study the fracture test results under different mixed mode load ing for LC4-M material,. a method for determing the direction of crack initiati o n growth in common fracture test is presented. Combined the compute and analysis about the stress triaxicity and the directions of the principal stresses near by the crack tip bearing different mixed mode loading, it could be concluded tha t, the position of crack initiation growth is at the place of maximal value of s tress triaxicity in the blunted zone of deformation near crack tip, even if crac k produce mode II shear breack in ductile material. The direction of crack initi ation growth is related to the direction of maximal tension stress at the point of initiation break for tension break. The direction of crack initiation growth is related to the direction of maximal shear stress at the point of initiation break for shear break.