转向架临界速度的不确定性研究

UNCERTAINTY ANALYSIS OF THE CRITICAL SPEED OF A RAILWAY BOGIE

铁道车辆临界速度与很多参量有关,如何准确有效地建立它们之间的函数关系进行不确定性研究是一个比较复杂的问题.基于此,推导高维多阶基于正态分布场的Hermite正交多项式,采用拉丁超立方采样的配点方式建立某转向架临界速度与随机参量之间的函数关系;分析了不同变异系数下转向架悬挂系统部件左/右、前/后均服从独立正态分布时临界速度的变化规律.可靠性分析的结果表明:随着变异系数的不断增大,只有取较低的临界速度限定值,才能保证转向架系统具有低的失效概率.灵敏度分析的结果则显示:二系悬挂横向阻尼对临界速度影响最大,不同的前/后悬挂部件对临界速度有着不同的重要性影响,变异系数的变化不会根本性改变参量的灵敏度指标排序.

The critical speed of railway vehicles is relevant to a lot of parameters.It is complicated to accurately and effectively construct functions among them for uncertainty analysis.In this paper,the high-dimensional Hermite orthogonal polynomial with high orders was derived based on the independent normal distribution,and the collocation method of Latin hypercube sampling was applied to construct the function with respect to the critical speed of a railway bogie with random parameters.The regularity of the critical speed with different variation coefficients was investigated on the condition that all the left/right and front/back suspension components of the bogie were independent normal distributions.It was indicated from reliability analysis that a lower limit value of the critical speed is the guarantee for low failure probability of the bogie with increasing variation coefficients.Moreover,the results of sensitivity analysis showed that the secondary lateral damping coefficient is the most important parameter to the critical speed.Different front/back suspension components usually have different influences to the critical speed.The rank order of sensitivity indices cannot be significantly impacted by the variation coefficients.