多轴变幅加载下GH4169合金疲劳寿命预测

摘要

对于GH4169合金进行多轴变幅加载,非比例附加强化效应是影响疲劳损伤的重要因素.使用可反映非比例附加强化效应及体现材料弹塑性状态的疲劳损伤模型对损伤曲线法进行修正.修正的损伤曲线模型不仅可考虑多轴载荷路径与载荷幅值的变化对疲劳寿命的影响,又可考虑多轴非比例附加强化效应同时不含材料常数.通过GH4169合金多轴变幅载荷块数据对该模型进行验证,其结果令人满意。%The effect of the additional cyclic hardening caused by the non-proportional loading is an important factor influencing fatigue damage for GH4169 superalloy under multiaxial variable amplitude loading.In this paper,the damage curve rule is modeled using the fatigue damage model,which takes into account not only the effect of the additional cyclic hardening caused by the non-proportional loading,but also the elastic-plastic stress state of material during the cyclic loading process.The model allows the non-linear effect of loading model and amplitude on fatigue damage at different load levels,also considers the effect of non-proportional loading,and does not include the material constants.The fatigue test data for GH4169 super alloy have been used to verify the model.Results show a good agreement for predicting fatigue damage under complicated multilevel loading.