2024-T3铝合金拉伸及剪切断裂行为

Tensile and shear failure mechanisms of 2024-T3 aluminum alloy

2024铝合金材料在拉伸和扭转载荷作用下表现出截然不同的失效机理。结合试验和数值方法,研究了应力状态对2024-T3铝合金韧性断裂行为的影响规律。首先,对圆棒和薄壁圆筒试验件分别进行了拉伸和扭转试验,从断面形貌以及断裂应变与应力状态间关系两个方面,考察了应力状态对2024-T3铝合金断裂机理的影响规律。然后,基于Gurson理论在商业有限元软件ABAQUS中开发了同时适用于拉伸和剪切断裂模式的细观损伤本构,对2024-T3铝合金的弹塑性响应和裂纹扩展路径进行了数值分析。与试验结果对比研究表明,本文发展的细观损伤本构能够较好预测延性金属材料在多种应力状态下的损伤破坏过程。

Under tensile and shear loading conditions, 2024 aluminum alloy exhibits two types of distinctive ductile rupture mechanisms. The growth and internal necking of voids governs the rupture mechanism in tension dominated loading mode, while the internal shearing in the ligaments between voids dominants for shear conditions. To investigate the influence of stress states on the material ductility of 2024-T3 aluminum alloy, tensile experiments of a smooth round bar and three notched round bars with different notch root radii as well as a pure torsion experiment were performed. Based on the modification of Gurson model by Nahshon and Hutchinson, avoid-based meso-damage constitutive relationship which can deal with both tensile and shear problems was developed and implemented in commercial software ABAQUS. The tensile and shear fracture behaviors of 2024-T3 aluminum alloy including the load-displacement response and crack propagation path were analyzed using the proposed approach and compared with experimental data. It is shown that the proposed approach can be used to predict the failure of ductile materials under complex loading conditions.