Numerical Analysis Of Vehicle-bridge Coupling Based On Random Vehicle Load

With the development of the transportation industry in our country,the number of bridges is also increasing.There are many factors that affect the durability of the bridge,and the vehicle load is undoubtedly one of which can not be ignored.According to the research category of the vehicle-bridge interaction,vehicle-bridge coupling vibration is a very important branch of it.Predecessors have done a lot of research on vehicle-bridge coupling vibration,but mostly concentrated in the vehicle to do uniform motion or uniform variable motion,less involved in the random variable motion is combined with the actual operation of it.This article is based on this point,with the the science and technology project of Jiangxi province transportation hall Mixed Traffic Flow Theory and Its Applied Research in Sub-health Bridge Bearing Capacity Evaluation(2014Y0012)and the project of Jiangxi province education hall Study on Optimal Damping Mechanism of Bridge under Random Vehicle Load with Multiple Damping Spatial Arrangement(GJJ160620)to study the axle coupling law of vehicle load with the random variable motion at a time,it has a certain theoretical value for the research of vehicle-bridge coupling vibration under the effect of the actual traffic load.The main contents of the study are as follows:(1)Firstly introduces the theory of CA module,and the vehicle's random motion module is established by its principle of acceleration and deceleration.The distribution function of actual vehicle load is obtained by MATLAB fitting and the random vehicle load database is established.This database has become the main part of the vehicle weight information subroutine.(2)By means of the theory of single-vehicle motion combined with the theory of CA model which is relevant and using MATLAB to establish the program of vehicle-bridge coupling vibration when the single car under uniform motion and random variable motion.Then two numerical results are compared and analyzed.Among these,the weight by the fixed value,the deck irregularity using AR model to simulate the mature.Sensitivity analysis is performed by changing the parameters of several vehicle-bridge coupling vibration.The results show that the uniform motion and random variable motion in weight,stiffness and length of the bridge is a regular parameter sensitivity.When the vehicle is in random motion,it is best to keep the vehicle speed in the 7-25m/s for the control of the vibration amplitude of the vehicle body and the maximum deflection of the bridge.The weightis 17.5t when the vehicle body vibration amplitude minimum.The maximum vertical deflection of bridge is with the increase of weight increasing but the weight is 22.5t of the bridge caused by the impact of the minimum.There is no consistent rule when analyzing the influence of deck irregularity.But the coefficient is 1.1.When the bridge stiffness increases,the upper and lower vibration amplitude of the lower body increases gradually.The maximum vertical deflection of the bridge is gradually decreased but the impact on the bridge is the smallest when the bridge stiffness is 2.600e11 N.m2.When the bridge length increases,the vibration amplitude of the lower body increases monotonically.The maximum vertical deflection of the bridge increases monotonically with the increase of the bridge length,and the impact on the bridge is same.(3)Based on the theory of vehicle-bridge coupling with multiple vehicle,the vehiclebridge coupled vibration program is established by using the same method.The uniform motion weight by using the fixed value representation.The random variable motion of vehicle weight using random vehicle load database for any vehicle enter into the bridge.Then the vehicle-bridge coupling vibration under random vehicle load is analyzed.And in the actual random movement of the random bridge,random acceleration and deceleration,random transformation.Then,the parameters of several vehicle-bridge coupling vibration are changed to analyze the sensitivity of the parameters,in which the law of the generated probability is not increased obviously.The results show that the uniform motion and random variable motion in weight,stiffness and length of the bridge all have a regular parameter sensitivity.Random variable motion,get off the vehicle body under the vibration amplitude increases with the average weight is almost monotonously.Analysis of bridge displacement.With the increase of average weight,the same displacement interval probability density occurred expanding.In addition,the maximum vertical deflection with the increase of mean weight increased gradually.The maximum vertical deflection of the bridge deck roughness showed a consistent sensitivity in bridge increases with the stiffness of 1.0.When the bridge length increases,the vibration amplitude of the upper and lower body and the maximum vertical deflection of the bridge show the same sensitivity.In addition,the location of the maximum displacement of the bridge is more than 0.8 of the probability density of the bridge is located in the 12~20m position of the interval,the vehicle body vibration amplitude occurs in the-0.05m~0.05 m interval is also with the probability density of 0.8.(4)Finally,the AR model is used to simulate the road surface roughness in the ANSYS,which is used to build the bridge deck pavement.Combined with the main structure model ofbridge,the bridge structure model with the road surface roughness is established.Then the random vehicle load information of a measured containing 100 cars by MATLAB processing into ANSYS for vehicle-bridge coupling analysis.According to the results of the ANSYS simulation can be seen that the results of multiple vehicle under random variable motion by numerical analysis of MATLAB have some theoretical value.