Impact Analysis And Damage Assessment Of Vehicle Impacting Pier Based On LS-DYNA

Urban roads and bridges connect the transportation network between cities and play a vital pivotal role.With the continuous increase of traffic volume,vehicle collision with pier accidents occur frequently.The research on vehicle collision with pier has important engineering application value.In this paper,the single column reinforced concrete pier is taken as the research object,the finite element analysis of vehicle pier collision is carried out,the formula fitting is carried out for the impact force of medium-sized truck hitting the pier,and the damage of the pier after impact is evaluated.The main research contents are as follows:(1)ANSYS / LS-DYNA is used to establish the model of trolley horizontal impact on reinforced concrete pier.The displacement time history curve and strain time history curve of impact point are compared with the test results of references to verify the correctness of the finite element model.(2)Using the verified finite element model parameters,a single column reinforced concrete pier model in Xuancheng City,Anhui Province is established.The vehicle model adopts the medium-sized truck model published by the national crash analysis center,which verifies the correctness of the medium-sized truck model.The effects of vehicle speed,vehicle mass,impact eccentricity and pier stiffness on the impact force of medium-sized truck hitting pier are studied,and the impact force is studied combined with the bivariate factors of vehicle speed and vehicle mass.The results show that the impact force is greatly affected by vehicle speed,vehicle mass and impact eccentricity,and the impact force is less affected by pier stiffness;The vehicle speed has a great influence on the impact force of the vehicle head hitting the pier and the impact force of the container hitting the pier.The vehicle mass only has a great influence on the impact force of the container hitting the pier.(3)The sensitivity of impact force is introduced to analyze the sensitivity of vehicle speed,vehicle mass and impact eccentricity.Using Levenberg Marquardt algorithm and python language,referring to the pier collision formula of ships in national specifications and the impact force formula given by scholars,the velocity mass impact force calculation formula of20 kinds of medium-sized trucks impacting concrete piers is fitted.The results show that the vehicle speed has the greatest influence on the impact force,followed by the vehicle mass,and the eccentricity is the weakest;The fitting effect of the impact force formula in the form of power function product is the best.(4)Analyze the plastic strain of the pier model under 25 groups of working conditions,compare the pier damage grade in relevant specifications,make damage evaluation for these working conditions,introduce the damage degree,calculate the damage degree for these working conditions,obtain the damage grade,and draw the damage thermal diagram.It is found that the evaluation of plastic strain is close to the evaluation of damage degree.The damage grade of damage degree calculation has the advantages of objectivity and easy calculation.By fitting and optimizing the light medium damage boundary and medium heavy damage boundary in the damage thermal diagram,a practical formula suitable for on-site evaluation is obtained.