Study On Stress Relaxation Acceleration Test Of C17500 Canted Coil Spring Of Beryllium Bronze

Canted coil spring is a kind of elastic element,which is widely used in the fields of airtight structure,electrical connection and mechanical locking in aerospace,medical equipment,new energy vehicle and high voltage power connection.Long time high temperature and high pressure working environment will lead to the reduction or even loss of resilience characteristics of elastic elements,that is,stress relaxation characteristics.In order to prevent seal leakage and connection failure,it is very important to study the stress relaxation characteristics of inclined coil spring and predict its service life.In this paper,the stress relaxation characteristics and life prediction of inclined coil spring are mainly studied as follows:(1)The uniaxial stress relaxation theory and the canted coil spring stress relaxation theory are established.Based on the analysis of uniaxial creep model and stress relaxation model,the transformation of creep theory to relaxation theory is realized according to the similarity of its generating mechanism,and the relaxation theory under uniaxial stress state is deduced.The stress analysis and stress analysis of canted coil spring are carried out,and the stress relaxation theory suitable for canted coil spring is established by combining with multiaxial creep theory.(2)The stress relaxation test equipment based on CTM 2500 tensile testing machine was developed.On the basis of the function of common tension and compression testing machine,temperature module addition and special fixture design are carried out to realize long-term performance testing of materials at different temperatures.(3)Research on the variation of parameters of uniaxial stress relaxation model.Relaxation tests of beryllium bronze C17500 under different loads and temperatures were carried out.The variation rule and prediction curve of model parameters were obtained by fitting the parameters of uniaxial relaxation model and test curve,which provided parameter support for the study of stress relaxation of canted coil spring.(4)The correctness of stress relaxation theory of canted coil spring is verified and its service life is predicted.The canted coil spring relaxation tests under different loads and temperatures are carried out.The service life prediction of the canted coil spring under normal working conditions is realized by using Arrhenius life prediction theory.The simulation relaxation curve is obtained by finite element analysis of the material relaxation parameters.The correctness of the multi-axis relaxation theory is verified by comparing the theoretical curve,the simulation curve and the relaxation test curve.The error analysis between the three is carried out,and the influence of spring structural parameters on the relaxation characteristics is analyzed by using finite element method.The reasonable suggestions for reducing the spring relaxation rate and improving the service life of canted coil spring are given from the aspect of structural parameter design.In summary,through the mutual confirmation of relaxation theory and relaxation test,the variation rules of model parameters are obtained,and the finite element analysis of canted coil spring relaxation characteristics and service life prediction are realized.