Residual Strength in Fatigue Based on the Strength-Life Equal Rank Assumption
Residual Strength in Fatigue Based on the Strength-Life Equal Rank Assumption
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DOI：
10.1177/002199837801200206
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发表时间：
1978-07
影响因子：
2.9
通讯作者：
Pei Chi Chou;R. Croman
中科院分区：
文献类型：
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作者：
Pei Chi Chou;R. Croman
导出了疲劳后剩余强度的分布方程。它们与几个石墨/环氧复合材料的实验数据进行了比较。该理论基于Hahn和Kim首先提出的假设，即对于给定的试样，其静态强度等级等于其疲劳寿命等级，或强度-寿命等等级假设。该方程包含一个自由参数，这是更通用的匹配实验数据。结果表明，疲劳过程中存在两个过程：一是疲劳破坏导致单个试件的退化，从而降低试件的平均强度;二是疲劳破坏导致弱试件的淘汰，从而提高试件的剩余平均强度。残余强度的变化可以是弱降解、强降解或强度增加。在所研究的试验数据中，有两个弱降解，两个强降解，两个强度增加。
Equations for the distribution of the residual strength after fatigue are derived. They are compared with experimental data for a few graphite/ epoxy composites. The theory is based on an assumption first introduced by Hahn and Kim, which states that for a given specimen its rank in static strength is equal to its rank in fatigue life, or the strength-life equal rank assumption. The equations contain a free parameter which is more versatile in matching experimental data. It is found that two processes are present during fatigue, one degradates individual specimens and tends to lower the mean strength, the other is the weeding out of weak specimens by fatigue failure which tends to increase the residual mean strength. The change of residual strength can be of weak degradation, strong degradation, or in crease in strength. Among the test data studied, two have weak degrada tion, two have strong degradation and two have increase in strength.