Analysis On Dynamic Characteristics Of Spring-steel Floating Slab Truck Bed In Subway

With the fast development of economic and comprehensive National Strength of our country,people's living standards continue to improve at the same time,but meanwhile,there are a lot of negative impact come too,such as fast increase in urban population,traffic congestion,etc.In recent years the development of the urban rail transit,provides a great convenience to solve such problems,but also the problem of vibration noise caused by urban rail traffic become more and more seriously which cannot be ignored.The vibration caused by the running subway train not only affects the driving safety and passenger comfort,but also affects the residents the normal life and precision instrument equipment around subway line.Therefore,the study of vibration noise reduction technology has become the key research object in the urban rail transit around the world.At present,the adoption of damping noise reduction technology in our country mainly include floating slab track,the ladder track,elastic support type without a frantic jumble orbit and various damping fasteners,etc.However,with its excellent damping noise reduction effect,floating slab track(FST)has been widely used in urban rail transit from country to country.This paper is based on the steel spring floating slab track as the research object,established steel spring floating slab track 3d finite element model by the large finite element software ANSYS for the modal analysis and transient dynamic analysis,especially focus on the influence to the former nine natural frequency of the structure and vertical vibration acceleration,vertical displacement of rail,floating slab track and inverted arch when the value of steel spring floating slab length,steel spring bearing stiffness,steel spring bearing spacing,floating slab track bed density changed.By the modal analysis,it shows that the natural frequencies of steel spring floating slab track structure is extremely low,with the increase of the length of floating slab track,the natural frequencies gradually reduced;with the increase of the support stiffness of the steel spring,the natural frequencies gradually increased;with the increase of space between steel spring,the natural frequencies gradually reduced;with the increase of the density of the floating slab track,the natural frequencies gradually reduced.Length of floating slab track bed largely effect on natural frequencies,floating slab track bed density averagely effect on the structure's natural frequency,both steel spring bearing stiffness and bearing spacing are greatly influence the first two order natural frequency of structure,and less influence on high order natural frequency.Because the steel spring bearing spacing has influence to the whole structural stiffness,so when design,both steel spring bearing stiffness and bearing spacing should be considered at the same time.Through transient dynamic analysis,it shows that with the increase of the length and destiny of Floating slab track bed,the vault of vertical vibration acceleration of rail,floating slab track and Inverted arch are all reduced,but with the increase of the steel spring bearing stiffness,they are all increased.However,with the increase of steel spring bearing spacing,the value of vertical vibration acceleration of rail and inverted arch are gradually reduced,but the value of vertical vibration acceleration of floating slab track is increased.For the Vertical displacement,with the increase of floating slab length and steel spring bearing spacing,the value of vertical displacement of the rail and floating slab track are increased,but with the steel spring bearing stiffness and the floating slab track density increase,it is reduced.