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本文研究了LY12铝合金板材,在过载比为2.0时的几种典型加载条件下的疲劳裂纹扩展行为。重点考虑了压缩过载的影响,并对其中前、后各施加一次单个拉伸和前、后各施加一次先拉、后压的过载试验,用线性累积法和Wheeler模型算法作了估算和比较。估算的结果表明:Wheeler算法对塑性区尺寸是敏感的,可以调整m值来拟合试验,其中包括压缩过载,能得到较好的结果。从工程估算角度,它可以通过试件、构件和全尺寸的各种谱载的疲劳试验,积累m值的分布规律,看来是当前较好的估算方法之一。
In this paper, the fatigue crack propagation behavior of LY12 aluminum alloy sheet under several typical loading conditions with an overload ratio of 2.0 was investigated. The influence of compression overload was considered, and a single tensile test was applied before and after each test, and the first and last overpressure tests were applied before and after each test. The linear cumulative test and the Wheeler model algorithm were used to estimate and compare them. The estimated results show that the Wheeler algorithm is sensitive to the size of the plastic zone and the m-value can be adjusted to fit the test, including compressive overload, resulting in better results. From an engineering estimation point of view, it can accumulate the distribution of m-values through fatigue tests of specimens, components and full-size spectrum loads, which appears to be one of the better current estimates.