螺杆泵挠性轴疲劳寿命可靠性分析

Reliability Analysis of Flexible Shaft's Fatigue Life of Screw Pump

针对螺杆泵挠性轴在使用中频繁发生断裂这一问题,用概率分析方法有针对性地给出其安全使用概率与寿命之间的关系。在计算挠性轴疲劳裂纹扩展寿命过程中,考虑几种主要参数的不确定性因素:初始裂纹长度、工况载荷、断裂韧性、裂纹扩展速率等,针对随机参数的分布特征,对其进行模拟实际操作工况抽样,应用MonteCarlo数值计算方法计算挠性轴寿命,得出可靠度随时间变化规律曲线。通过对计算结果的分析,找出挠性轴设计中存在的问题,并提出相应改进意见。

Aiming at high frequency of the fracture of screw pump＇s flexible shaft, the relationship between the probability of sureness and the use life of flexible shaft was given by adopting the method of probability analysis. During the process of calculating the fatigue crack＇s extend life of flexible shaft, the uncertainty of several main factors was taken into consideration： initial crack length, practical working load, fracture toughness and crack propagation rate. According to distribution characteristics of random parameters, a sample was given by means of simulating practical operational working condition, then the life of flexible shaft was computed by using Monte Carlo numerical calculating method. A curve that reliability varied with time was obtained. By analyzing the calculation result, the problem existed in the design of flexible shaft was found out and corresponding improvement measure was put forward.