• CN:11-2187/TH
  • ISSN:0577-6686

›› 2009, Vol. 45 ›› Issue (1): 111-114.

• 论文 • 上一篇    下一篇

蠕变-热疲劳交互作用的力学机理

闫明;孙志礼;杨强;何雪浤   

  1. 沈阳工业大学机械工程学院;东北大学机械工程与自动化学院
  • 发布日期:2009-01-15

Mechanical Mechanism of Creep-thermal Fatigue Interaction

YAN Ming;SUN Zhili;YANG Qiang;HE Xuehong   

  1. School of Mechanical Engineering, Shenyang University of Technology School of Mechanical Engineering & Automation, Northeastern University
  • Published:2009-01-15

摘要: 随着航空航天、能源和化学工业的发展,高温设备的应用越来越广泛。这些设备在稳态运行中受到蠕变损伤,在起动、停车或工况突变时受到热疲劳或热机械疲劳损伤,潜在危险性极大,一旦发生事故往往是灾难性的。考虑材料的双线性随动强化性质和蠕变特性,研究蠕变-热疲劳交互作用的力学机理,得到如下结论: ①升温和保温过程生成的压缩非弹性应变(塑性应变和蠕变应变)越多,降温过程产生的拉应力和拉应变越大,设计受蠕变-热疲劳损伤的构件时宜优先选择具有较高压缩屈服点和较低蠕变速率的脆性材料。②蠕变影响着循环的应力幅和平均应力,并使它们经历一定数量的循环后达到稳定状态,可以把蠕变-热疲劳损伤等效为热机械疲劳损伤,从而使寿命预测和试验简单可行。

关键词: 交互作用, 热机械疲劳, 蠕变-热疲劳, 寿命预测

Abstract: With the development of aerospace, energy and chemical industry, the high temperature equipment is used more and more widely. Such equipment is subjected to creep damage during steady-state operation and thermal fatigue or thermo-mechanical fatigue damage in the frequent on-off operation or the sudden change of operating mode, its potential danger is great , once an accident happens, it is always catastrophic. The mechanical mechanism of the creep and thermal fatigue interaction is studied by considering the bilinear kinematic hardening property and creep characteristics of the material. When the interaction occurs: ① The more the compressive inelastic strain generated in the temperature rising and holding process is, the greater the tensile stress and strain generated in the cooling process will be. Therefore, brittle material with high compressive yield limit and low creep rate should be preferred in designing the components subjected to creep-thermal fatigue damage. ② Creep affects the stress amplitude and the mean stress of the cycle, and makes them stable after a certain number of cycles. Thus, the creep-thermal fatigue damage can be equaled to thermo-mechanical fatigue damage, which simplifies the life prediction and failure test.

Key words: Creep-thermal fatigue, Interaction, Life prediction, Thermomechanical fatigue

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