中文摘要：

通过实车试验，获得自行火炮扭力轴的随机载荷谱。采用材料的分段折线式循环应力、应变幅曲线，将改进的二阶矩法与Neuber法结合，提出计算扭力轴应力集中处局部应力、应变随机性的方法。根据随机性分析结果，获得由材料和载荷随机性引起的扭力轴局部应力、应变的概率密度函数，通过二重积分得到联合概率密度函数。结果表明，扭力轴同时具有高周和低周疲劳现象。结合工程实际提出计算不同工况下两种疲劳模式概率的方法，通过进一步研究可以得到自行火炮扭力轴的疲劳可靠性。研究方法对于工程机械装备疲劳可靠性分析和评估具有参考价值。

英文摘要：

An experiment was carried through the field test to achieve the load spectrums of torsion shaft of self-propelled gun. The Neuber rule and the improved second moment criterion were used to analyze the randomness of the local stress-strain of torsion shaft based on the recycle stress-strain subsection curve of metal. The probability density functions of the local stress- strain were achieved, which were caused by the randomness of materials and loads, and the joint probability density functions of the local stress-strain of torsion shaft were achieved by double integral. The result shows that the torsion shaft fatigue can be both high cycle fatigue and low cycle fatigue, and the method to calculate the probabilities of the two fatigue models was provided. The fatigue reliability can be deduced by further studies.