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采用Iosipescu和双缺口拉伸实验,对车用铝合金(5052)在剪切和准剪切应力条件下的大变形和损伤机制进行研究。断口分析和有限元三向应力度计算表明纯剪切条件下材料主要以剪切滑移带变形并萌生微裂纹,基本不产生孔洞损伤。而准剪切条件下材料损伤存在有微孔洞和剪切带混合并发机制。高三向应力度区首先出现微孔洞裂纹起始,但随着损伤向剪切应力区过渡,三向应力度不断降低,孔洞的长大聚合受到抑止,转而出现剪切滑移带中的平行微裂纹,材料最终主要以剪切滑移失效。
Iosipescu and double notched tensile test were used to study the mechanism of large deformation and damage of automotive aluminum alloy (5052) under shear and quasi-shear stress conditions. Fracture analysis and three-dimensional finite element stress calculation show that the material under pure shearing conditions mainly deforms and sprouts microcracks with shear slip band, and basically does not produce hole damage. However, under the conditions of quasi-shearing, there are mixed mechanisms of microporous and shear banding. In the high three-stress region, the initiation of microcavity cracks first appears, but as the damage transitions to the shear stress region, the three-direction stress decreases continuously, and the growth and aggregation of the pores are inhibited, and the shear slip band appears instead Parallel to microcracks, the material eventually fails in shear slip.