航空学报 > 1989, Vol. 10 Issue (12): 659-661

疲劳裂纹起始扩展门槛值的研究

刘文珽   

  1. 北京航空航天大学
  • 收稿日期:1989-04-14 修回日期:1900-01-01 出版日期:1989-12-25 发布日期:1989-12-25

RESEARCH OF FATIGUE CRACK INITIATION GROWTH THRESHOLD

Liu Wenting   

  1. Beijing University of Aeronautics and Astronautics
  • Received:1989-04-14 Revised:1900-01-01 Online:1989-12-25 Published:1989-12-25

摘要: 1.疲劳裂纹起始扩展门槛值(△K_(th))的概念 人们通常提到的疲劳裂纹扩展门槛值△K_(th)是在裂纹扩展过程中不断下降△K,使裂纹扩展不断减慢,直至停止扩展时所对应的△K值。它由降K程序测定,试验方法见文献。达到△K_(th)时裂纹前缘塑性区很小,在厚度和应力比一定的条件下,△K_(th)是材料常数。然而,在构件承受变幅交变载荷作用时,某级载荷使裂纹尖端产生应力强度因子K_(fmax),对应

Abstract: A new threshold,the fatigue crack initiation growth threshold(ΔKth)i,is proposed in this paper. It is showed by test research that the(ΔKth)i values corresponding to given Kfmax under the same material and stress ratio don't change with crack length, and the functional relationship between (ΔKth)i and Kfmax is nearly linear.