Reliability Copula Model for Wind Turbine Gearbox Based on Failure Correlation

On the basis of each gear’s failure correlation, the reliability Copula model of a wind turbine gearbox is established and a 1.5 MW wind turbine gearbox is taken as the research object. Firstly, based on the dynamic reliability model of mechanical parts, each gear’s life distribution function of a wind turbine gearbox is obtained.The life distribution function can be used as the marginal distributions of the system’s joint distribution. Secondly,Copula function is introduced to describe the failure correlation between parts, and the appropriate Copula function is selected according to the shape characters of Copula probability density function. Finally, the wind turbine gearbox system is divided into three parts according to the failure correlation of each gear. The Sklar theorem and the thought of step by step analysis are used to obtain the reliability Copula model for a wind turbine gearbox based on failure correlation.     

基于IDEPSO-SS的多工况转向架构架可靠性分析

基于子集模拟(Subset Simulation,SS)方法求解结构失效概率,再采用改进差分进化粒子群算法(IDEPSO)优化每层样本个数和初始条件概率,以获得单工况下结构最优失效概率,并结合几何分析确定联合失效概率,计算多工况下结构失效概率,确定最优失效次序。以某型转向架构架为研究对象,先采用SS方法建立构架各工况下每层样本个数和初始条件概率关于结构失效概率的响应面代理模型;再采用IDEPSO算法计算各工况下每层样本个数和初始条件概率的最优值,计算构架单工况下最优失效概率;最后,采用几何分析确定多工况下的联合失效概率,并结合二阶窄边界法和最优准则获得构架多工况下最优可靠度和最优失效次序。结果表明:基于IDEPSO-SS获得的单工况构架最优失效概率,在保证计算精度的同时,较传统方法计算效率提高了96%;最优失效次序下构架的多工况失效概率高于传统方法,提高了多工况转向架构架可靠性分析的准确性。