Research On Multi-source Excitation And Topology Optimization Of Dynamic Response For Wind Turbine Gear System

Under the challege of global problems such as energy crisis and climate change,the wind power generation technology gets attention all around the world,the demand on high power and reliability of wind turbine is promoted.Performance of wind turbine gear system influences reliability of whole wind turbine,as for the multi-source exciattion analysis and dynamic reponse topology optimization,they are of great importance to wind turbine gear system design.Wind power generation technology is interdisciplinary,the nonconforming contact of cylindrical gear transmission is locally nonlinear,these factors affect the accurate analysis of external and internal excitation of wind turbine gear system;the accuracy and efficiency of vibration prediction for wind turbine gear system under dynamic excitation affect the feasibility of dynamic response optimization of wind turbine gear system,at the same time,for the large scale optimization problems of topology optimization based on variable density method,the efficiency of solving optimization problem also directly influences the feasibility of dynamic response optimization of wind turbine gear system.Taking wind turbine gear system as study object and focusing on multi-source excitation and dynamic response topology optimization of wind turbine gear system,researches about the external excitation analysis,the internal excitation analysis,the system vibration prediction and influence factor analysis,the system dynamic response topology optimization are carried out,which offers references for low weight and vibration,high reliability design of wind turbine gear system.The main contents of this paper are as follows:(1)The autoregressive method is adopted to simulate the time varying wind field,the aerodynamic load of blade is calculated on the basis of blade element and momentum theory,the influence of wind speed,rotor speed and blade pitch on power coefficient is analyzed;the blade is divided as nonlinear Euler beam element of general bending,the dynamic model of rotating flexible beam is established on the basis of floating frame of reference formulation,the influence of aeroelastic coupling on blade aerodynamic load is analyzed;the rotor speed and blade pitch are controlled on the basis of variable speed pitched control theory,the drive chain model is established to simulate the dynamic reponse of wind turbine,the external dynamic excitation of wind turbine gear system is calculated.(2)The complex potentials in tooth deformation expression are calculated through analytical integration of Hertz contact distributed load,the tooth contact point stiffness and gear system stiffness excitation are calculated on the basis of conformal mapping method;in consideration of diversity of magnitude and distribution for gear error,the error excitation of gear system is calculated on the basis of composite meshing error;the realistic meshing in position of gear transmission is determined on the basis of off-line engagement model to calculate the impact excitation;the influence of working condition,gear macro and micro parameters on internal excitation is analyzed.(3)The dynamic analysis finite element model of wind turbine gear system is established,the vibration reponse of wind turbine gear system is calculated on the basis of mode superposition method,the vibration reponse of test point on gearbox surface is measured and compared;the degrees of freedom are reduced for transmission sub structure on the basis of component mode synthesis method,its effectiveness is verified through calculation result comparison of eigenfrequency and root mean square value of vibration response;the vibration response of wind turbine gear system is calculated on the basis of harmonic reponse method,the vibration response considering different frequencies is compared to calculation results of transient dynamic response method;the influence of external excitation,gear parameter and housing parameter on vibration response of wind turbine gear system is analyzed.(4)On the basis of variable density method,the topology optimization model of wind turbine gear system under multiple static and dynamic constraints is established,the adjoint method is adopted to calculate sensitivity of harmonic displacement,dynamic compliance,eigenfrequency,consdensed stress and static compliance;the simplified dual programming is adopted to solve Lagrange multipliers,the moving asymptotes function is adopted as sequential explicit convex approximation of constraint function,the improved optimality criteria method is presented to solve topology optimization problems under multiple constraints,while assumption of active topological variable set and active constraint set is avoided;the dynamic reponse topology optimization of wind turbine gear system under multiple static and dynamic constraints is solved by improved optimality criteria method,the stiffener layout and housing structure are optimized.