Miner累积损伤理论的试验验证和统计分析

 本文通过对LY12-CZ铝合金板材光滑试件和中心孔试件的常幅加载和变幅加载疲劳试验,对Miner累积损伤理论进行了试验验证,并对累积周比的分散性作了统计分析,发现累积周比的分散性服从Weibull分布,因此本文提出以最小累积周比值或以与一定存活率相应的累积周比值进行安全寿命估计的观点。

TEST VERIFICATION OF MINER'S RUIE AND STATISTICAL ANALYSIS

The fatigue tests of smooth specimens and specimens with a central hole under constant and variable amplitude loadings are presented. The material is LY12-CZ aluminum alloy. Taylar and Freudenthal program block spectrums are adopted for variable amplitude loading. Miner's rule is verified by the tests. The statistical analysis of fatigue life and cumulative cyclic ratio is completed.It is found from the tests:（1） The average Rvalue of equals 0.96 for Taylar programblock spectrum and 1.20 for Freudenthal one. Miner's rule is not too different from test data.（2） The kind of the spectrum has an effect on the value of a due to the effect of residual stress.（3） Fatigue life in the constant amplitude tests under high stress is submitted to log-normal distribution and to weibull distribution under low stress.（4） The dispersal of a is submitted to weibull distribution. As a result, the minimum value α0 or probability value αp can be used to estimate the safe life.