孔洞型缺陷对铸造铝合金应力分布影响的研究

Study on effect of void defects on stress distribution of cast aluminum alloys

铝合金在铸造过程中往往会生成孔洞型缺陷,这些缺陷容易造成应力集中进而影响材料的疲劳性能;不同缺陷对应力分布的影响是不同的,量化分析不同缺陷的影响有利于确定缺陷的危害程度。首先,对孔洞型缺陷进行简化建模,将缺陷简化为球体或椭球体进行量化分析;然后,利用ABAQUS软件对简化模型进行有限元分析,研究了缺陷深度、缺陷间距离、缺陷外形等3个缺陷特征对应力分布的影响;最后,对有限元分析结果进行分析,得到了缺陷特征和应力集中系数的非线性数学关系表达式。可为铸造铝合金试件的损伤检测提供一定理论参考。

Void defects are often generated in aluminum alloys during the casting process,and these defects tend to cause stress concentration and thus affect the fatigue properties of the material.The effects of different defects on the stress distribution are different,and the quantitative analysis of the effects of different defects is beneficial to determine the degree of harm of defects.Firstly,the void defects were modeled in a simplified manner,and the defects were simplified to spheres or ellipsoids for quantitative analysis.And then,finite element analysis of the simplified model was carried out using ABAQUS software to study the effects of three defect characteristics,such as defect depth,inter-defect distance and defect shape,on the stress distribution.Finally,the finite element analysis results were analyzed to obtain the expressions for the nonlinear mathematical relationships between the defect characteristics and the stress concentration coefficients.It can provide a certain theoretical reference for damage detection of cast aluminum alloy specimens.