Research On Active/Robust Life Extension Control For Steel Railway Bridges With AMD

With the wide construction of long-span bridges and the wide application of efficient construction materials,the vibration problem of the railway steel bridge is progressively prominent.Railway steel bridge,as a common structure of large span bridge,plays a vital role in the safety of railway operation.Railway steel bridge is subjected to the increasingly heavy traffic loads because of the increasing number of operation trains and the improvement of the train velocity.The vibration problem of the steel bridge is not only related to their normal use and durability,but also related to the train running safety.It will have the important economic value and social value in ensuring the normal use of the steel bridge,preventing the occurrence of major accidents and prolonging the service time of the bridge by adopting vibration control method to reduce the dynamic response of the bridge when high-speed train passing by.Taking a railway steel truss bridge as the engineering background,the vibration control and the assessment of crack initiation life of railway steel bridge under active control and robust control is researched in this paper during the train running.According to the existing domestic and international research status of the vibration control and the assessment of crack initiation life analysis,and the actual current study,the research focuses on the following aspects:Firstly,the related engineering background of this paper is briefly introduced,the integral shell model of the railway steel truss bridge by using finite element analysis software is established,and the dynamic characteristics is analyzed and the plane layout of AMD system and the mechanical model are given.The integral model of railway steel bridge is reduced based on model reduction method,and the structural stability and the error influence of reduced-order model is analyzed.Secondly,the controlled equations of not controlled,active controlled and robust controlled bridge under the action of train load are given,the vibration response of the whole railway steel bridge under the action of train load is researched,and the railway bridge vibration effect under the three conditions are compared.The effect of active control and robust control of bridge under different vehicle speed is studied.Thirdly,the crack initiation life of railway steel bridge under active control and robust control is researched during the train running.The node of railway steel bridge is established by using finite element analysis software.The dangerous point is determined with the strain analysis of the joint model under the action of train load,and the steps of the multi-axle fatigue analysis of the railway steel truss bridge are given by using the critical surface method.Finally,multi-axis fatigue life analysis of railway steel truss bridge is made by using the critical surface method,and the fatigue crack initiation life of the railway steel bridge nodes after the control is obtained.The fatigue life of the railway steel bridges under no control,active control and robust control is compared.At the same time,the crack initiation life of railway steel bridges with different speed of the train waking under active control and robust control is researched.In summary,a set of the vibration control theory and the assessment of crack initiation life of railway steel bridge under the effect of trains walking is established in this paper.The active/robust vibration control method can reduce the dynamic response of the bridge when the train passing through the bridge and it has a certain economic and social benefits in ensuring the normal use of the steel bridge,improving the resistance to fatigue damage,preventing the occurrence of major accidents and reducing the maintenance costs of the bridge.