兰州理工大学学报 ›› 2024, Vol. 50 ›› Issue (4): 43-49.

• 机械工程与动力工程 • 上一篇    下一篇

基于应力梯度和附加强化的多轴疲劳寿命建模

刘俭辉*, 王杰, 华飞龙, 赵贺   

  1. 兰州理工大学 机电工程学院, 甘肃 兰州 730050
  • 收稿日期:2022-02-28 出版日期:2024-08-28 发布日期:2024-08-30
  • 通讯作者: 刘俭辉(1985-),男,河南睢县人,博士,教授.Email:liujh@lut.edu.cn
  • 基金资助:
    国家自然科学基金青年基金(51605212),兰州市人才创新创业项目(2021-RC-23)

Multiaxial fatigue life modeling based on stress gradient and additionalhardening

LIU Jian-hui, WANG Jie, HUA Fei-long, ZHAO He   

  1. School of Mechanical and Electronical Engineering, Lanzhou Univ. of Tech., Lanzhou 730050, China
  • Received:2022-02-28 Online:2024-08-28 Published:2024-08-30

摘要: 鉴于Manson-Coffin方程未考虑应力梯度和附加强化的影响,以及缺口附近非均匀应力场和非比例附加强化对疲劳损伤演化过程的影响,建立了适用于多轴缺口件的疲劳寿命预测模型.首先,考虑裂纹萌生和扩展的物理机制,借助坐标变换原理和临界面理论,以最大剪切应变幅为损伤参量确定临界面位置;其次,分别对临界面的正应力和剪应力进行归一化处理,提出了考虑多轴应力集中系数和应力梯度影响指数的等效应力梯度因子;同时,考虑相位差、路径非比例和材料非比例对疲劳寿命的影响,提出了新的非比例附加强化因子;最后,结合Manson-Coffin方程建立了考虑应力梯度和非比例附加强化的多轴疲劳寿命预测模型,并将该模型、Manson-Coffin方程、LV模型和FS模型的预测寿命与实验寿命进行对比,结果表明该模型的预测精度优于其它3种模型的.

关键词: 多轴缺口件, 应力梯度效应, 非比例附加强化效应, 寿命预测, 临界面法

Abstract: Considering the influence of non-uniform stress field and non-proportional additional hardening on the fatigue damage evolution process, a fatigue life prediction model for multiaxial notched specimens is established to solve the problem that the stress gradient and additional hardening effect are not considered in Manson-Coffin equation. Firstly, considering the physical mechanism of crack initiation and propagation, the location of the critical plane is determined by using the maximum shear strain amplitude as the damage parameter based on the coordinate transformation principle and the critical plane theory. Secondly, the normal stress and shear stress on the critical plane are normalized, and the new equivalent stress gradient factor is determined considering the multiaxial stress concentration factor and stress gradient influence index. Meanwhile, taking into account the influence of phase difference, path non-proportion, and material non-proportion on fatigue life, a new non-proportional additional hardening factor is proposed. Finally, a new multiaxial fatigue life prediction model is proposed based on the Manson-Coffin equation. The prediction life of the proposed model, Manson-Coffin equation, LV model, and FS model are compared with the experimental results. The comparison results show that the prediction accuracy of the proposed model is better than the other three models.

Key words: multiaxial notched specimens, stress gradient effect, non-proportional additional hardening, fatigue life prediction, critical plane method

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