In order to investigated the reason of friction plate failure in the yaw brake of megawatt wind turbine under low speed and heavy load conditions,the direct thermal coupling method was used to simulate the equivalent stress and temperature change characteristics of the yaw friction plate under braking conditions.Based on the orthogonal test method,through intuitive analysis and variance analysis,the influence of yaw pressure,yaw speed,and friction coefficient on the maximum equivalent stress and maximum temperature of the friction plate was studied.The results show that the equivalent stress and temperature of the friction plate increase with the increase of the yaw pressure,and there exists stress and high temperature concentration at the entrance of the friction plate.The yaw pressure has the greatest influence on the maximum equivalent stress and the maximum temperature of the friction plate,followed by the friction coefficient,and the yaw speed has the least influence.The weight ratios of the influence of yaw pressure,yaw speed,and friction coefficient on the maximum equivalent stress are 1,0.06,and 0.48,respectively,and the weight ratios on the maximum temperature are 1,0.91,and 0.97 respectively.By reasonably selecting the yaw operating conditions,the alternating concentration area of the equivalent stress and temperature distribution of the friction plate can be alleviated,thereby prolonging the service life of the friction plate,and then providing theoretical guidance and data reference for the design of the yaw brake.