Abstract:

Rainflow cycle counting and linear damage rule were used to calculate fatigue damage for SWT, KBM, FS and LKN criteria by previous test results. The effects of the maximum damage plane, which was as the critical plane on previous criteria were discussed. It is shown that comparing with the maximum shear/normal strain approach, the predictions are improved by using the maximum damage plane approach, part nonproportional paths for SWT, AV and part nonproportional paths for KBM, TV paths for FS. But for LKN, the predictions are nonconservative for some paths by this approach than that of the maximum shear/normal strain approach. The critical plane was chosen according to the weight function approach. For KBM and FS criteria, the better predictions were gained. While for SWT and LKN criteria, the unconservative predictions were gained for some paths. The quantity evaluation of different criteria was done by using several statistic parameters.

Key words: nonproportional loading, rainflow cycle counting, maximum damage plane, critical plane

摘要：

利用已有的试验结果,结合SWT、KBM、FS和LKN四种寿命估算模型,采用雨流计数方法和线性损伤律进行低周疲劳寿命预测,比较并分析了将最大损伤面作为临界面对各模型的影响。结果表明,与最大剪应变/正应变面方法相比,最大损伤面方法提高了SWT模型的部分非比例路径的预测结果及KBM模型AV路径和部分非比例路径的寿命预测结果。对于FS模型,最大损伤面方法使TV路径得到了偏于安全的结果;但对LKN模型,该方法对部分路径得到了比最大正应变面更为危险的结果。考虑权函数的影响重新确定临界面进行预测,使KBM模型和FS模型的预测结果得以改善,而对SWT模型和LKN模型,部分预测结果偏于危险。采用统计特征参量对各模型的预测能力进行了定量评价。
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关键词: 非比例载荷, 雨流计数方法, 最大损伤面, 临界面