疲劳载荷分布形式对构件寿命的影响

Effect of Different Distribution Condition of Fatigue Loads on Fatigue Life

1. Department of Power Engineering in College of Mechanical and Electric Engineering, Hebei Science and Technology University, Shijiazhuang, Hebei, 050018, China;
2. Nanjing University of Technology, Nanjing, 210009, China

摘要: 采用数学软件模拟正态分布、对数正态分布和伽玛分布3种不同疲劳载荷变化范围(S)的分布形式,针对S选择相同的均值(S)和不同的变异系数(C),计算在这3种载荷分布形式下构件的疲劳寿命N_rand,同时与采用恒定的载荷变化范围(S=S)计算得到的疲劳寿命N_avg进行对比,发现当S较小时,结构疲劳寿命N_rand随变异系数C的增大先增大后减小;当S较大时,结构疲劳寿命N_rand随着载荷分散性的增大而单调减小。
- 分布载荷 /
- 裂纹扩展 /
- 疲劳寿命
Abstract: In this article, 3 distribution styles, i.e, normal distribution, log-normal distribution and Gamma distribution, are used to simulate the variety of fatigue loads S. Same average value of fatigue loads variety S and different coefficient of variation C are adopted in every distribution style, and corresponding fatigue life N_rand and the average fatigue life Navg in the condition of S=S are calculated. By comparing the fatigue life N_rand and N_avg, a rule can be found that when the average value of fatigue loads variety is small, the fatigue life will first increase and decrease later with the increasing of the coefficient of variation, and when the average value of the fatigue loads variety is large, the fatigue life will always decrease while the coefficient of variation increases.
- Distributed load /
- Crack growth /
- Fatigue life