Damage Evolution and Life Prediction of Low Cycle Fatigue for Magnesium Alloys under Asymmetrical Stress Loading

Abstract

Abstract: Low cycle fatigue damage evolution of magnesium alloys under asymmetrical stress loading was analyzed， where the changes of elastic modulus, equivalent modulus, total strain energy density, and mean strain were selected as damage variables. And then, a corresponding life prediction models was developed. Results show that the low cycle fatigue damage evolution of the magnesium alloys under asymmetrical stress loading may be described by the changes of total strain energy density or mean strain as damage variables, and the corresponding life prediction models have good effectiveness. Damage curve of the mean strain changes, as the damage variable, has better representation in comparison.

Key words: magnesium alloy, asymmetrical stress loading, low cycle fatigue, fatigue life, damage variable

摘要： 将弹性模量、等效模量、总应变能密度及平均应变的变化作为损伤变量，对镁合金非对称应力载荷下的低周疲劳损伤演化进行分析，建立了相应的寿命预测模型。结果表明：选取总应变能密度或平均应变的变化作为损伤变量可以描述镁合金非对称应力载荷下的低周疲劳损伤演化，相应的寿命预测模型预测效果较好；选取平均应变的变化作为损伤变量所得损伤曲线具有更好的代表性。

关键词: 镁合金, 非对称应力载荷, 低周疲劳, 疲劳寿命, 损伤变量

CLC Number:

CHEN Ling1, 2;ZHANG Xianming1;LIU Fei2;OUYANG Ping1;JIA Yanyan3. Damage Evolution and Life Prediction of Low Cycle Fatigue for Magnesium Alloys under Asymmetrical Stress Loading[J]. China Mechanical Engineering.

陈凌1,2;张贤明1;刘飞2;欧阳平1;贾艳艳3. 镁合金非对称应力载荷下的低周疲劳损伤演化和寿命预测[J]. 中国机械工程.

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