Multi-objective Structure Topology Optimization Of Brake Pad In Large-megawatt Wind Turbine Brake

Wind turbine brake is the key part of mechanical braking in wind turbine braking system.As the development of wind turbine towards to large-megawatt level,it is difficult for existing wind turbine brake to meet the working condition of high speed and heavy load.As the direct executive component while mechanical braking,brake pad has a direct impact on braking performance of large-megawatt wind turbine brake.According to the actual working condition of the brake pad in large-megawatt wind turbine,it is of great significance to improve the braking performance of large-megawatt wind turbine brake by using multi-objective structure topology optimization to design the brake pad.In view of problems of brake pad in existing large-megawatt wind turbine brake,such as uneven wear,vibration,shake and scream during braking progress,deformation caused by frictional heating,this paper begins with the known mechanical property of brake pad in large-megawatt wind turbine brake.Static characteristics,dynamic characteristics and thermal-structural coupling of the brake pad are all analyzed,as well as the braking progress of large-megawatt wind turbine brake in this paper.The minimum requirement of brake pad which is designed after structure optimization needs to meet is summarized.Based on finite element method and variable density topology optimization method with SIMP,combined with multi-objective compromise programming theory,after analyzing the static and dynamic characteristics of brake pad with the actual working condition of large-megawatt wind turbine brake,static structure topology optimization,static and dynamic multi-objective structure topology optimization and static and dynamic multi-objective structure topology optimization with the effect of thermal-structural coupling of the brake pad are analyzed respectively in this paper.Reconstructed models are built according to every topology structure,accuracy of each model is tested under each working condition.The influences of both dynamic vibration frequency and friction heat on structure optimization of brake pad are analyzed according to each topology optimization.The result shows that design of brake pad according to actual working condition can make the stress distribution more even and the use rate of braking material higher.The design of holes in certain place of brake pad is good for controlling the vibration,shake and scream during braking progress,meanwhile,it should contain enough material to conduct the friction heat.The research progress of this paper provides theoretical foundation and design reference for designing the structure of brake pad in large-megawatt wind turbine brake,which also provides solution for solving multi-objective problems in the application of structure topology optimization methods.The establishment of mathematical model in multi-objective structure topology optimization with the effect of thermal-structural coupling provides reference in the application of continuum topology optimization methods with coupling field conditions.