• CN:11-2187/TH
  • ISSN:0577-6686

›› 2011, Vol. 47 ›› Issue (18): 72-79.

• 论文 • 上一篇    下一篇

基于新裂纹扩展驱动力参量的焊接接头疲劳裂纹扩展的研究

熊缨   

  1. 浙江工业大学机械工程学院;浙江工业大学特种装备制造与先进加工技术教育部重点实验室;浙江工业大学浙江省特种装备制造与先进加工技术重点实验室
  • 发布日期:2011-09-20

Fatigue Crack Driving Force Parameter for Crack Growth in Welded Joint

XIONG Ying   

  1. College of Mechanical Engineering, Zhejiang University of Technology Key Laboratory of Special Purpose Equipment and Advanced Processing Technology of Ministry of Education, Zhejiang University of Technology Zhejiang Provincial Key Laboratory of Special Purpose Equipment and Advanced Processing Technology, Zhejiang University of Technology
  • Published:2011-09-20

摘要: 传统上疲劳裂纹扩展速率以一个参量——应力强度因子幅(PARIS模型)或有效应力强度因子幅(ELBER模型)来表达。PARIS模型不能统计应力比效应和变幅加载历史。ELBER裂纹闭合模型虽被广泛应用,但确定其开闭口载荷的测量方法很多,且测量结果均存在主观性。最近研究表明,疲劳裂纹扩展不仅依赖于应力强度因子幅,还与最大应力强度因子有关。并且KUJAWSKI提出了两参量模型,该模型避开了有争议的裂纹闭合效应。基于一个载荷循环中柔度变化与裂纹尖端开闭口与弹塑性行为的关系,提出一个新的具有物理意义的两参量驱动力模型。针对Q345钢焊接接头各区域进行两种应力比R=0.1和0.5的疲劳裂纹扩展试验。使用该模型针对Q345钢焊接接头各区域的疲劳裂纹扩展数据进行验证。结果表明,提出的新模型在预测应力比对裂纹扩展速率的影响时比上述三个模型更有效。

关键词: 迟滞回线, 开闭口, 裂纹扩展驱动力模型, 疲劳裂纹扩展, 应力比

Abstract: Traditionally, the fatigue crack growth rate is described by one parameter-the stress intensity factor range (PARIS model), or the effect stress intensity factor range (ELBER model). PARIS model can not explain stress ratio effect and variation amplitude loading history. ELBER’s crack closure model has been widely accepted as a dominant mechanism influencing fatigue crack growth behavior. But the opening load or closure load is determined based on different measurements, and there is an inaccuracy problem by the manual operation after experiment. It is generally accepted that the fatigue crack growth (FCG) depends mainly on the stress intensity factor range and the maximum stress intensity factor. Recently, KUJAWSKI proposed a two-parameter crack driving model, which does not invoke disputable crack closure data. This paper focuses on the physical meaning of compliance changes caused by plastic deformation at the crack tip, an improved two-parameter driving force model is proposed. The model is successfully verified using fatigue crack growth data obtained for Q345 steel welded joint under two stress ratio R=0.1 and 0.5. Presented results indicate that new model is equally effective or better than above three models from literature in correlating and predicting the R-ratio effects on fatigue crack growth rate.

Key words: Crack growth driving force model, Crack opening/closure, Fatigue crack growth, Hysteresis loop, Stress ratio

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