【摘要】 基于传统拖拉机作业工况复杂、轴类零部件受多重载荷耦合作用易损坏以及配套耐久性台架试验操作复杂、费用昂贵、试验时间长等问题,提出了一种能模拟实际循环工况、简化加速传动系轴类零部件耐久性试验的程序载荷谱编制方法。针对拖拉机田间犁耕作业工况,建立了动态扭矩测试系统,可抵抗土壤-机器-植物系统多重相互载荷干扰,准确获取传动系传动轴随机载荷谱。应用雨流计数法与数理统计方法,计算实测载荷谱二参数均幅值载荷分布规律,其中均值服从对称正态分布,幅值服从威布尔分布;进而求取均幅值二维联合概率密度函数,编制程序载荷谱并简化。应用有限元法与疲劳分析方法进行传动轴疲劳寿命预测,从疲劳损伤分布与程度两个方面对危险部位寿命进行比较分析。试验结果表明,在实测随机载荷谱和编制简化的加速程序载荷谱分别作用下,传动轴的疲劳损伤分布与程度基本一致,验证了程序载荷谱的准确性与加速性。本文所研究的加速程序载荷谱对农业装备其他关键零部件的耐久性台架试验具有一定的参考价值与指导意义。更多还原

【Abstract】 Based on the problems of complex working conditions of traditional tractors, easy damage of axle parts under multi-load coupling and complicated operation, high cost and long test time of matching durability bench test, a program load spectrum compilation method which can simulate actual cycling conditions and simplify the durability test of axle parts of accelerating transmission system is proposed.According to the working conditions of tractor ploughing in the field, a dynamic torque testing system is established, which can resist the mutiple mutual load interference of soil-machine-plant system and accurately obtain the random load spectrum of transmission shaft.Based on rain-flow counting method and statistical theory, the distributions of mean and amplitude are found to confirm with normal distribution and Weibull distribution respectively.Then the two-dimensional joint probability density function of the mean and amplitude is obtained, and the program load spectrum is compiled and simplified.The fatigue life of transmission shaft is predicted by using finite element method and fatigue analysis method.The fatigue life of dangerous parts is compared and analyzed from the distribution and degree of fatigue damage.The test results show that the fatigue damage distribution of the transmission shaft is basically consistent with the degree under the action of the measured random load spectrum and the simplified acceleration program load spectrum.The accuracy and acceleration of the program load spectrum are verified.The accelerated program load spectrum studied in this paper has certain reference value and guiding significance for the bench test of durability of other key components of agricultural equipment.更多还原