超高强度钢超高周循环下疲劳裂纹扩展寿命研究

摘要

Based on Paris crack growth theory,because of the different of the rate of crack growth in different ranges,we divide the crack growth life into three ranges:below threshold corner growth,small crack growth and long crack growth.Integration of Paris formula in each range,then add the three ranges into together,we will get the total life of crack growth.Compared to Paris formula,this method gets higher life of crack growth.But all of them cannot discredit the fact:the total fatigue life is decided by the initial of crack, and the life of crack growth is much less than the experimental life.%以Paris裂纹扩展理论为基础,根据不同阶段裂纹扩展速率不同,将裂纹扩展分为三个阶段:低于始裂门槛值阶段、短裂纹扩展阶段和长裂纹扩展阶段.在每个阶段对Paris裂纹扩展公式分别进行积分,最后将三个阶段寿命相加,即可得到裂纹扩展总寿命.此方法所得到的裂纹扩展寿命较Paris公式略高,但是不会改变疲劳总寿命主要由疲劳裂纹萌生决定,裂纹扩展寿命远小于试验总寿命这一事实.