Strength Analysis And Optimization Design Of Track Fasteners

Rail fastener is an important part of connecting rail and sleeper,which plays an important role in ensuring the stability and reliability of track.The fatigue failure of fastener promotes the damage of track and vehicle structure parts,and even endangers the driving safety.Therefore,it is necessary to study the mechanical properties of fastener system.Based on the finite element theory,the contact stress calculation and mechanical analysis of bending stress of type Ⅱ spring fastener and type III spring bar fastener suitable for passenger rail and heavy load track are carried out in this paper.Finally,the optimal design of type Ⅱ spring fastener is carried out.The wheel/rail vertical force and the wheel-rail lateral force are calculated by the vehicle/track coupling dynamics theory method,and the force state of the fastener spring is analyzed.Using the nonlinear contact theory,a finite analysis model of two elastic strip fastener systems was established.The finite element method is used to study the mechanical properties of contact and bending of two elastic strip fastener systems.The distribution of the equivalent stress of the fastener spring surface subjected to external load after the fastener system is installed is analyzed.The case where the strip bends the equivalent stress and deformation.The results of contact stress show that with the increase of rail train speed and axle load,that is,the increase of external load,the maximum contact equivalent stress of the elastic bar increases nonlinearly,plastic deformation occurs at the contact part,and the stress concentration is at the load.Cycling may cause crack initiation.The results of bending stress and deformation indicate that in the linear orbit,the type II and III fastener springs increase with the external load,and the deformation exceeds the range of the elastic range of the elastic bar,which causes the elastic buckle pressure to decrease.The bending stress of the elastic bar exceeds the yield strength,which causes the elastic deformation of the elastic bar.In the curved orbit,the increase of the external load causes the displacement of the type II elastic bar to exceed the working range of the elastic stroke,affecting the buckle pressure and the plasticity of the elastic bar.Deformation,the type III elastic strip is elastically deformed and the displacement is within the working range of the warping range.Based on the calculation results of contact stress of the fastener projectile,the optimum design of the structure and size of the II type projectile strip shows that the optimized projectile contact and other effect forces are smaller than the yield limit and elastic deformation occurs,so as to prolong the service life of the projectile strip.