The Study On Raising Speed Limit For The Arch Bridge By Vibration Numerical Analysis Based On LS-DYNA

With the rapid development of transportation infrastructure,bridge accounted for a large proportion of total highway mileage,as of 2014,China has built the bridge has reachedmore than 700 000.How to effectively maintain and use of the bridge has been built,to maximize its value,it will become an important future direction of development of bridge engineering.There have been nearly a hundred years of history for vehicle-bridge coupling research,simplified and efficient vehicle model has always been the focus of research,vehicle-vehicle model development and progress of the bridge Coupling is almost the same.Thesis show relies on cn LS-DYNA software to establish a simplified finite element model of triaxial heavy-duty trucks,and three-dimensional finite element model of the bridge-interaction coupling between the vehicle and a bridge for vehicle cruise state and state with a uniform variable were discussed.The main work is as follows:(1)introduce the establishment of triaxial heavy truck model and Arch model,focusing on the relationship between the components of the vehicle finite element model and arch finite element model,and dynamic calculation mechanism,and verified the correctness of the model.(2)analysis the vehicle and the simple beaminteraction mechanism,at a constant speed and variable speed vehicle,got the bridge dynamic response Subjected to the a constant speed and variable speed vehicle.The results showed when vehicle runningwith a constant speed,the bridge midspan vertical displacement changes a little,but the midspan vertical displacement deflection curve fluctuates more obvious when vehicle run slower;midspan vertical displacement and vertical acceletation and stress valueare significant differences when vehicle acceleration,indicating that the vehicle acceleration enhanced impact effect significantly.(3)Analysis vehicle-bridge interaction mechanism based on vehicle and arch finite element,separately study arch bridge dynamic response at a constant speed vehicle and a change speed vehicle,considering multiple factors,compare the arch bridge dynamic response in different conditions.The results showed when vehicle running with a constant speed,the continuous beam midspan and arch midspan vertical displacement changes a little,but the midspan vertical displacement deflection curve fluctuates more obvious when vehicle run slower.midspan vertical displacement and stress valueare significant differences when vehicle acceleration,acceleration motion and deceleration motion are similar,indicating that the vehicle acceleration enhanced impact effect significantly,should reduce change vehicle speed when running as possible.Through this study,as the Arch Bridgemanager,in the daily management,when traffic is small,the vehicle unimpeded access,we can not limit the driving speed of the vehicle;when large traffic flow and traffic congestion,try to keep the vehicle at a low speed state,reducing the adverse impact action.