Study On Fatigue Performance Of Mid-mounted Shear Hinges On Steel Spring Floating Plate Tracks In The Curved Section Of Subway

At the present stage,the mileage of rail transport lines in China has exceeded 9,000 kilometres.Due to the encryption of the line network,the growth of track service time,the frequency of the increase in the impact of factors such as rail traffic caused by vibration and noise problems have become more difficult problems.Steel spring floating plates are widely used in vibration and noise reduction sections.In order to suppress the vertical misalignment between the floating plates and extend the service life of the track,shear hinge devices are often installed at the joints of the floating plates.At present,shear hinge support rod fracture,bolt breakage,fixed pieces of loose and other diseases occur frequently,but for shear hinge research is relatively limited,so this paper to shear hinge on the research object,the main research content is as follows.(1)A refined finite element model of the mid-mounted shear hinge is developed to analyse the mechanical properties and force transfer mechanisms of the shear hinge.The stress levels and contact states of the shear hinge components under different operating conditions are calculated to determine the locations of the most dangerous stress points.In addition,three conditions of failure of the shear hinge are set up and the effect of the shear hinge on the other shear hinges and track components of the group under different failure conditions is analysed.(2)A vehicle-track rigid-flexible coupling dynamics model is developed for small radius curved sections of the metro to analyse the effects of shear hinges on the vehicle system and track system.The curved track model partly takes into account the curve widening and over-height factors.The rail and track plate are modelled using 3D solid units,the fasteners and steel spring vibration isolators are modelled using spring damping units,and the shear hinge is modelled using bending shear springs.The effect of the shear hinge on the vibration characteristics of the vehicle body,frame and wheel pairs in the vehicle system,the vibration response of the rail and track plate in the track system,the displacement difference between the track plate ends and the support reaction force of the fasteners are investigated to obtain the excitation load history and to evaluate the role of the shear hinge in the vehicle-track system dynamics.(3)A refined finite element model of the shear hinge is combined with a rigid-flexible kinetic model to investigate the effect of vehicle operating speed on the fatigue performance of the shear hinge.The Mises equivalent force time curve at the hazard point of the shear hinge is obtained through the simulation,and then the fatigue damage of the shear hinge is quantified and the fatigue life is predicted by combining the rainflow counting method,Goodman’s mean stress correction and fatigue damage accumulation theory.By revealing the effect of travel speed on the fatigue performance of the shear hinge,it provides a feasible reference for the optimal design of the shear hinge and the actual operation and maintenance of the steel-spring floating plate track.