Simulation Analysis Of The Mechanical Characteristics Of Anchor Bolts Of Subway Steel Spring Floating Plate Track Fasteners

While the construction of urban rail transit is in full swing,the problem of vibration and noise caused by the operation of the vehicle is becoming more and more serious,and more and more vibration damping measures are applied to the track structure.As one of the vibration-absorbing structural forms,the steel spring floating plate has the advantages of good vibration absorption performance,long life,convenient maintenance and adjustable stiffness of the vibration isolator,and is often used in schools,residences and hospitals where high vibration damping performance is required.However,in the process of long-term operation of the subway,the steel spring floating plate track structure itself will have diseases such as steel spring failure and fastener anchor bolt breakage.Therefore,this paper conducts the following research on the fracture phenomenon of anchor bolts of ordinary fasteners on steel spring floating plate tracks:(1)A finite element model of ordinary fasteners was established,the assembly sag and lateral stiffness of the fastener are calculated,the stress changes and deformations at the stress danger points of the anchor bolt under the two states of installation and rail head bearing sag and transverse most unfavorable concentrated force load are analyzed,and the most unfavorable position of the bolt force is determined.(2)The rigid-flexible coupling model of the vehicle-steel spring floating plate track in the straight and curved sections was established,and the effects of vehicle speed,steel spring vertical stiffness and curve radius on the dynamic response of the track structure were analyzed.At the same time,the influence of the vertical stiffness of the steel spring on the stress at the stress danger point of the bolt and the stress change at the bolt danger stress point at different positions on the inside and outside of the curve were studied.(3)Combined with the calculation results of the fastener system dynamic response,the stress state and fatigue life of the anchor bolt are analyzed by taking the displacement response of the rail head area as the fatigue load of the fastener system.The results show that reducing the vertical stiffness of the steel spring will reduce the fatigue life of the bolt,so the influence of vibration damping and fastener bolt disease needs to be considered when designing the track structure.In addition,the fatigue life of the non-working edge of the bolt on the inside and outside of the curve is lower than that of the working edge,and in the process of bolt design and processing of the finished product,it is necessary to consider factors such as bolt thread,bolt rod diameter and shape of the gusset plate.