Experimental And Numerical Study On Performance Of Composite Bridge Protection Structures

With the increasing number of vehicles and total mileage of highway,the probabilities that vehicles collide bridge piers are increasingly higher in China.The bridges design with the demands of specification may be damaged in the collision of vehicle,the accidents will cause severe loss of properties and casualties.In order to decrease the damage that piers suffer in collision,a type of bridge protection structure with the constructure of steel and GFRP honeycomb sandwich was designed in this paper.What’s more,the trolley test and numerical simulation were used to investigate the crashworthiness of this structure.Then,a structural design method was proposed that bases on the impact force and penetration obtained from simulation simulation,and achieves an optimal design of structure.The main detailed contents are as follow:Firstly,the trolley collision test was designed and implemented,the original acceleration data and ultimate deformation were obtained in test.The filter method was choosed to process the original data to acquire the velocity and kinetic energy and impact force curves in collision process.The maximum impact force in test is lower than the equivalent static force of specification,which indicates that bridge protection structure satisfies the design demand with the impact speed of 40 km/h;Then,the test scenario was simulated by LS-DYNA software and the numerical simulation data were obtained and compared to the data in test.It is indicates that the numerical results are similar with that in test and the FE models that are validated by test and can be applied in latter investigation of structural crashworthiness.Besides,the crashworthiness of variety of constructures were discussed and the results indicates that the constructure with steel-honeycomb sandwich has the best protection ability and the assembly of thinner steel and thicker honeycomb has the good capacity to decrease the impact force and prolong the duration;Acquiring the impact response in actual cars impact by LS-DYNA and discussing the structural crashworthiness under actual impact with the comparison of trolley impact.The results indicates that the trolley impact overestimates the impact response,and original bridge protection structure satisfies the protective demand within most impact speed.Because of lower structural dimension,it can not provide enough protection to medium sized vehicle.At last,this paper propose a structural design method based on results of actual car impact to predict the penetration and impact force by kinetic energy and suggest the proper structures towards different types of vehicles.The response surface method was applied to optimize the bridge protection structure to obtain the structural dimension with best crashworthiness.