基于应力强度干涉模型的疲劳损伤研究

基于Miner法则，分析了工程上常用的阶梯谱级数对疲劳寿命精度的影响．建立了变换的JS-N曲线与阶梯谱拟合曲线的应力强度干涉数学模型，采用参数求解的数值解析法得到参数，并推导出了疲劳损伤的积分公式．对铁路货车转向架侧架运行36万公里（一个段修期）内分阶段的多次载荷谱测试数据进行分析，得出随着各阶段阶梯谱离散级数的增大，损伤成收敛趋势，寿命预测精度高．采用本文的分析方法，建立了侧架一个段修期的载荷谱概率模型，预测了侧架的寿命及其可靠性．

Research of Fatigue Damage Based on the Mathematic Model of Stress Interference

According to the Miner principle, the effect of ladder spectrum usually used in valuation of iatigue life was analyzed. The stress interference of mathematic model of transform S--N curve and fitting curve of lad- der spectrum was founded. The parameter was gained by using numerical analytic method, and the integrabel formula of fatigue damage was also derived. The test data of many load spectrums which were got from railway freight car bogie sideframe with in 360000 kilometers （a depot repair period） were analyzed, and the rule of convergence trend about the ladder of load spectrum and fatigue was founded, which can improve life prediction accuracy. Using the method mentioned above, one probability model of ladder spectrum about side of bogie was constructed, and the reliability of fatigue life about the side of bogie was estimated.