• CN:11-2187/TH
  • ISSN:0577-6686

机械工程学报 ›› 2019, Vol. 55 ›› Issue (10): 54-61.doi: 10.3901/JME.2019.10.054

• 材料科学与工程 • 上一篇    下一篇

基于均布临界域本征损伤耗散的疲劳极限等量关系

彭艳1, 李浩然1, 刘洋1, 章健2   

  1. 1. 燕山大学国家冷轧板带装备及工艺工程技术研究中心 秦皇岛 066004;
    2. 滨州学院机电工程学院 滨州 256600
  • 收稿日期:2018-09-15 修回日期:2019-01-25 出版日期:2019-05-20 发布日期:2019-05-20
  • 通讯作者: 彭艳(通信作者),男,1971年出生,博士,教授,博士研究生导师。主要研究方向为金属板带轧制技术和结构件损伤分析与延寿。E-mail:pengyan@ysu.edu.cn
  • 作者简介:李浩然,男,1990年出生,博士研究生。主要研究方向为构件疲劳强度预测。E-mail:lihaoranysu@163.com;刘洋,男,1991年出生,博士研究生。主要研究方向为构件冲击疲劳行为。E-mail:liuyang863@aliyun.com
  • 基金资助:
    国家重点研发计划资助项目(2017YFB0306402)

Fatigue Limit Equivalent Relation Based on Uniform Intrinsic Damage Dissipation in Critical Domain

PENG Yan1, LI Haoran1, LIU Yang1, ZHANG Jian2   

  1. 1. National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao 066004;
    2. School of Mechanical and Electrical Engineering, Binzhou University, Binzhou 256600
  • Received:2018-09-15 Revised:2019-01-25 Online:2019-05-20 Published:2019-05-20

摘要: 疲劳极限预测是工程结构件复杂载荷下抗疲劳设计重要基础。应力场强理论,无法给出考虑平均应力的疲劳极限关系,属于临界域准则,而临界点准则无法刻画高周疲劳损伤局部域特点,与高周疲劳损伤特点不相吻合。基于连续介质损伤力学及其不可逆热力学框架,建立一种基于高周疲劳损伤临界域本征损伤耗散的疲劳极限等量关系模型。该等量关系包括考虑拉压异性的含平均应力的拉伸疲劳极限和对称旋转弯曲疲劳极限与对称扭转疲劳极限之比。运用含平均应力的拉伸疲劳极限预测模型,对两种常见铝合金LC4和LC9进行寿命预测,结果表明所提模型优于现有的单一线性(GOODMAN和THORDBERG)和GERBER椭圆疲劳极限等量关系模型,与试验吻合较好,单一线性疲劳极限等量模型无法刻画拉压异性。利用对称旋弯-对称扭转疲劳极限比值预测模型分别对11种常见金属材料疲劳性能进行预测,结果表明所提模型明显优于基于应力场强法导出的比值预测模型。基于均布临界域本征损伤耗散开展疲劳极限预测,为金属材料疲劳强度预测研究提供了新思路。

关键词: 本征损伤耗散, 临界域, 疲劳极限, 寿命预测, 损伤力学

Abstract: Fatigue limit prediction is an important basis for anti-fatigue design of engineering structures under complex loads. The stress field strength theory can not give the fatigue limit relation considering mean stress and belongs to the criterion of critical region. The criterion of critical point can not describe the local characteristics of high cycle fatigue damage, which is inconsistent with the characteristics of high cycle fatigue damage. A fatigue limit equivalence relation model for high cycle fatigue, which is based on intrinsic damage dissipation in critical region, is established by means of continuum damage mechanics and its irreversible thermodynamic framework. The equivalence relation includes the tensile fatigue limit under mean stress considering the tension-compression anisotropy and the ratio of the symmetrical rotational bending fatigue limit to the symmetrical torsional fatigue limit. The life predictions of LC4 and LC9 aluminium alloys is carried out using the prediction model for tensile fatigue limit under mean stress. It is shown that the proposed model is superior to the existing models associated with fatigue limit equivalence relations of single linear (GOODMAN and THORDBERG) and GERBER elliptic, and in good agreement with the test results. The anisotropy of tension and compression can not be described using the single linear equivalent model for predicting fatigue limit. The fatigue properties of eleven kinds of common metal materials are predicted using the model for predicting the ratio of symmetrical bending-torsion fatigue limit, and it is shown that the proposal is superior obviously to the ratio prediction induced by stress field intensity approach. That fatigue limit prediction based on uniform intrinsic damage dissipation in critical domain provides a new idea for fatigue strength prediction of metal materials.

Key words: critical region, damage mechanics, fatigue limit, intrinsic damage dissipation, life prediction

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