Front Rail Development Based On Vehicle Platform Schematization

The designed parameters of vehicle front rails are important as front rails are highly related to the crashworthiness of vehicle.The platform design of the front rails structure should take the impact energy of various vehicle into consideration so that the front rails structure is applicable for different kinds of vehicle with high safety performance.This paper developed a design method for front rails that can be used in the development of various types of vehicle with good impact performance to shorten development cycle,reduce cost and improve product competitiveness.The main contents of this paper are as follows.(1)The overall safety performance target and the corresponding goals of sub items were determined according to the requirements of vehicle platform,laws and regulations,and market evaluation.The front rails' energy absorption ratio in the collision energy conversion process and the crush distance in the impact process were acquired by researching the structure and load path of benchmark vehicle,developing and analyzing FE models.(2)The overall collision energy of platform vehicle was calculated to decide the energy which the front rails need to absorb based on the range of platform vehicle kerb masses.Then the average load of collapse energy absorption based on the crush distance of front rails was computed.A variety of combination computations including different cross-section sizes,thicknesses and material yield strengths were completed referring to the theory of thin-walled beam collapse which elaborates the relationship between crush force and other parameters of front rails.Furthermore,the optimal combination was selected which satisfied the loading value of the platform front rails considering the packaging and lightweight requirements to decide the basic parameters of platform front rails.Finally,the loading value of front rails reached the setting targets by means of developing sub collision models of front rails and conducting FE analysis and component test validation.(3)Accurate material parameters were obtained based on the results of high-speed tensile test.The complete vehicle FE model was built and analyzed.Meanwhile,the reinforcing plates of front rails were optimized.Finally,both of the front rails structure and platform vehicle structure were proved to meet the crashworthiness requirements according to the full vehicle deformation,front rails deformation,vehicle acceleration and firewall intrusion in the simulations and tests.This study completed the design of front rails of platform vehicles and determined the platform crashworthiness development method through benchmarking,FE analysis and theory application.The method was proved to be feasible and effective by the final test validation.And it can ensure the platform of vehicle engineering solution and realize the platform development of body structure,which has a high application prospect.