• CN:11-2187/TH
  • ISSN:0577-6686

›› 2009, Vol. 45 ›› Issue (9): 285-290.

• 论文 • 上一篇    下一篇

一种新的多轴疲劳寿命预测方法

李静;孙强;李春旺;乔艳江;张忠平   

  1. 空军工程大学理学院
  • 发布日期:2009-09-15

New Prediction Method for Multiaxial Fatigue Life

LI Jing;SUN Qiang;LI Chunwang;QIAO Yanjiang;ZHANG Zhongping   

  1. The Science Institute, Air Force Engineering University
  • Published:2009-09-15

摘要: 已有的试验结果表明,非比例加载过程中主应变轴在循环变形中连续旋转,导致多滑移系开动,阻碍了材料内部形成稳定的位错结构,从而产生非比例循环附加强化现象,导致疲劳寿命降低。由此,以薄壁圆管拉扭疲劳试件为研究对象,在分析临界面上的应变变化特性的基础上,基于多轴疲劳临界损伤面原理,应用von-Mises准则提出一种能够同时适用于比例与非比例加载的多轴疲劳损伤参量,并进行了平均应力修正。新的损伤参量,在考虑了临界面上最大剪应变范围和正应变范围对多轴疲劳损伤贡献不同的同时,还考虑了非比例加载下产生的附加强化对材料多轴疲劳寿命的影响。该参量不含有材料常数,便于工程应用。经正火45钢,S460N 钢,1045HR钢,高温Haynes 188合金,高温GH4169合金五种材料的多轴疲劳试验验证,预测结果与试验结果吻合较好。

关键词: 比例与非比例加载, 多轴疲劳, 附加强化, 临界平面法, 寿命预测

Abstract: Existing test results show that during non-proportional cyclic loading, the continuous rotation of principal strain axis in cyclic deformation leads to actuation of multi-slip systems which hinder the forming of stable dislocation substructures inside the material. As a result, the material show additional hardening upon non-proportional cycling. The increased cyclic hardening by non-proportional loading reduces the fatigue life. Therefore, with the analysis for the state of the strain on the critical plane of the thin-walled cylindrical specimen, a new damage parameter for multi-axial fatigue is proposed by means of von-Mises criterion based on the critical plane approach. In addition, the effects of the mean stress on the fatigue life are analyzed as well. The new damage parameter considers maximum shear strain range and normal strain range on the critical plane, and the effect of the additional cyclic hardening caused by the non-proportional loading on the fatigue life is taken into account as well. It is convenient for engineering application because of no material constants in this parameter. The predicted multi-axial fatigue lives of the materials studied (steel 45, S460N steel, 1045HR steel, Haynes 188 alloy and GH4169 alloy) by using the proposed damage model are found in good agreement with experimental results.

Key words: Additional cyclic hardening, Critical plane approach, Life prediction, Multiaxial fatigue, Proportional and non-proportional loading

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