Rail Connecting Parts-Contact Mechanics Analysis And Optimization Design Of Fishplate

Fishtail plate,also known as rail joint splint,is an important part for two rails to butt joint.Its function is to connect two rails and make them transition smoothly.The mechanical properties of fishplate material will affect the stability and safety of train operation.The failure or fracture of fishplate will aggravate the wear and tear of track,destroy the normal working state of track joint connection system,and also lead to the damage of other parts of vehicle structure,seriously endangering the safety of train operation.Therefore,the mechanical properties of fishplate is an important factor affecting the safe operation of vehicles,and the mechanical research of fishplate is an indispensable part in the process of railway development.In this paper,based on the finite element theory,the contact mechanics analysis of fishplate of 60kg/m rail is carried out.According to the results of the mechanical analysis,the fishplate of 60kg/m rail is optimized.According to the nonlinear contact theory of the model,the finite analysis model of fishplate is established.The contact performance of the finite element model of fishplate is analyzed,and the internal stress,surface contact equivalent stress distribution and deformation displacement of fishplate are obtained.The results show that: in the straight section of rail,the rail will be subjected to vertical load and small transverse load,and the contact stress and displacement of fishplate increase slowly with the increase of speed;In the rail curve section,the rail is subjected to both lateral and vertical loads,and the contact stress and displacement of fishplate increase slowly with the increase of speed.The stress concentration is distributed in the contact area between rail and fishplate and around the bolt hole of fishplate.In this paper,the effect of rail gap size on stress distribution of fishplate is considered.Due to the change of the external environment temperature,the track will expand and contract.This paper takes the temperature change in winter and summer in Northeast China as an example.In winter,the rail shrinks and the rail gap becomes larger;In summer,the rail expands and the rail gap decreases.According to the calculation formula of rail gap,the stress distribution of fishplate under different rail gap values: 8mm,12 mm,16mm and20 mm is analyzed.The results show that the maximum equivalent stress of fishplate increases significantly with the increase of rail gap.In this paper,the structure of fishplate is optimized,and the shape of bolt hole of fishplate is changed.The stress change of bolt hole is studied and analyzed,so as to prevent the generation and extension of cracks in this area.The calculation results show that: after the change of bolt hole shape,the maximum stress value of fishplate decreases not very obviously,only by about 2.4%,but the maximum stress value of bolt hole decreases significantly,about 30.4%,which achieves a good optimization effect.Compared with before optimization,the fishplate after optimization is more difficult to crack,which can prolong its service life and achieve the purpose of optimization.