Study On Dynamic Load-bearing Characteristics For Rubber Elastic Brackets Of Wind Turbines

The problem of noise，parts wear caused by vibration when the windturbine generator unit work is urgently needed to avoid， with thecharacteristics of low quality, high bearing etc., rubber material productsbecome indispensable part of wind turbine，mainly used for support，damping. Because of the bad working environment，condition is complexand changeable，a reasonable assessment of the dynamic load performanceis crucial for engineering design of rubber elastic product. The spring anddashpot is used mainly by the classical theory of mechanical vibration todescription bearing and damping properties of the shock absorber orvibration isolator，when it was used to characterization the mechanicalproperties of dynamic bearing of rubber elastic product，because of its bothbearing and damping characteristics，and it has the characteristic ofnonlinearity on the bearing characteristics and damping characteristics，need to do further research. This thesis studies mechanical properties ofdynamic bearing on rubber elastic product，to the rational use rubber elasticproduct、provide technical guidance of engineering design，has the practicalsignificance.In this paper，in rubber elastic support of wind turbine generator unitas the object，study on dynamic load performance，mainly the followingthree aspects of work was implemented：Firstly, this paper analyzes mechanism of formation of the dynamic，static bearing performance of rubber elastic product—energy loss andcreep，based on the theory of mechanical vibration，the complex stiffnessconcept was introduced, according to the Darren Bell principle，dynamicsmodel of wind vibration system is established；In rubber elastic support ofwind power as object，bearing characteristics and damping mechanism ofrubber material under cyclic loading is analyzed，expression of the complexstiffness of rubber elastic product are derived，characterization bearing anddamping characteristics of rubber elastic element，the dynamic bearingperformance of elastic rubber product is reasonably described，and theparameters of real part of complex stiffness is defined as elastic stiffness， different from the static stiffness of the classical model of vibrationsystem；Based on the elliptical rules by national standard GB/T15168-94<vibration and shock isolator performance test methods>，the expressionsof elastic stiffness and damping factor of complex stiffness is obtained.Secondly，on the basis of the theory of complex stiffness of rubberelastic support dynamic bearing capacity， influence factors undermechanical loading of dynamic bearing performance of rubber elasticsupport is analyzed，based on orthogonal experimental design，withfrequency, amplitude and the preload of mechanical loading asexperimental factors respectively，the dynamic bearing performance test ofrubber elastic support is conducted. the frequency, amplitude and preloadcorrelations of elastic stiffness, damping factor is analyzed according toexperimental results，the significant of experimental factors is distinguishedby the method of variance and range，the results show that：the order of thesignificant of influencing factors of dynamic bearing performance of rubberelastic support is frequency、amplitude、preload of load respectively.Then，based on the hyperelastic constitutive theory of rubber material，using the ABAQUS finite element analysis software，combined basicmechanical test data of rubber material， three kinds of hyperelasticconstitutive model—Mooney-Rivlin, Ogden, Van der Waals was selected toparameter fitting，model parameters is obtained；an axisymmetric finiteelement model of rubber elastic support is established by using the finiteelement software ABAQUS，the numerical simulation of dynamic bearingcharacteristics of rubber elastic support is conducted，and the simulationcalculation results of stiffness and damping factor were compared withresults of dynamic bearing properties test of rubber elastic support，conclusion show that：for the compressing and shearing loads, suitable forselect Van der Waals model；Mooney-Rivlin model suitable for loads ofsmall and medium-sized deformation；while the three order Ogden model ismore suitable for large deformation load. The different constitutive modelssuitable for different bearing conditions，in order to improve the accuracyof the finite element simulation，reasonable selection of constitutive modelis particularly important.Finally，the main work and conclusions are summarized，and theprospect of the future research work.