Reliability Analysis Of Wind Turbine Gearbox Base On Physics Of Failure Relativity

The wind turbine is the key equipment of wind turbine system.Gearbox as the main transmission part of the wind turbine,with long life and high reliability and other technical requirements.For wind turbine gearbox,the failure-dependence is a common phenomenon,it often leads to excessive error when ignoring system's failure dependency.The failure-dependence existing in the wind turbine gearbox main has two aspects.On the one hand,the components in the gearbox have a variety of failure modes,the failure-dependence exists in between different failure modes;On the other hand,due to being affected by the same input torque,there is a failure-dependence between different components in the gearbox.Therefore,we depend on the two aspects and the 1.5MW horizontal axis wind turbine gearbox to study the reliability of wind turbine gearbox and its parts from the perspective of physics of failure.The main findings include the following three aspects:(1)For the failure-dependence between different failure modes of each individual gear in wind turbine gearbox,comprehensive considering the stress-dependence and strength-dependence,combining formula of total probability,establishing the failuredependence joint distribution of considering strength degradation.Analyzing the reliability of wind turbine gearbox from the failure mechanism and nature.(2)Use stress-strength model of physics of failure and combine strength degradation to establish the joint distribution of failure-dependence of the failure of parts.Revealing that the essence of failure-dependence is that it has a certain mapping correlation among the common random variables of strength and stress from the perspective of physics of failure.And explores the reasons for the formation of such a mapping correlation.The results show that the main reason for the formation of such a mapping correlation is fluctuation and dispersion of the common random variables of strength and stress.(3)For failure-dependence between different components in wind turbine gearbox,based on mechanism of failure-dependence of wind turbine gearbox,get the fault tree model of failure-dependence of wind turbine gearbox.For the failure of parts of wind turbine gearbox fault tree,from the perspective of physics of failure,use stress-strength model of physics of failure and combine strength degradation to establish the joint distribution of failure-dependence of the failure of parts,get the reliability model of wind turbine gearbox based on physics of failure under common cause failure.