Study On Lightweight Design Of Automotive B-pillar Reinforced Plate With Carbon Fiber Reinforced Plastic Material

The surge of interest in lightweight which contributes greatly to energy saving and emission reduction have attracted increasing attention in the field of automotive industry.The Carbon Fiber Reinforced Plastic(CFRP),a kind of lightweight materials,is equipped with unusual properties,including lightweight,high strength and design ability.Compared with the application research of CFRP automotive exterior parts,there is less attention on the study of composite materials' applications in auto body structures.The B-pillar is a relatively independent structural component on the vehicle body.The assembly includes an inner plate,an outer plate,and a reinforced plate.In order to ensure the rigidity of the entire vehicle in case of side impacts,the part often includes a plurality of reinforced plates,but it is not ideal from the perspective of structural assembly and lightweight design of the vehicle body.Because of the certain representativeness of B-pillar in the body structure,the design of other structural parts of the body frame can be used for reference by studying its equal generation design of CFRP.This thesis selects the B-pillar assembly that is the typical main frame structure of the vehicle body as the research object and carries out the following research:The research status of the application of CFRP in automobiles was analyzed.The mechanical properties of composites,the failure criteria of single-layer plates,and the strength theory of composite laminates were studied.This will provide a theoretical basis for the design,optimization,analysis and verification of CFRP automotive B-pillar Reinforced Plate.CFRP laminates were manufactured using Resin transfer molding(RTM),mechanical testing was performed using a testing machine,and mechanical properties of composites were obtained according to ASTM standards.Including tensile strength,modulus,Poisson's ratio and other parameters,provide material parameters for the subsequent finite element analysis of CFRP.According to the typical force characteristics of the B-pillar structure,the typical stress conditions of the assembly are determined and its stiffness is solved.The finite element method was used to analyze the original steel assembly and the stiffness of the original metal material assembly was determined.These stiffness parameters will serve as design constraints in the optimization design.The CFRP structure was designed according to the principle of equal stiffness based on the topological optimization of the steel B-pillar reinforced plate,and optimized by the size optimization and layup sequence,and the finite element simulation model of the composite material was established.Comparing the stiffness properties of the original metal and CFRP B-pillar assembly under typical operating conditions,it can be found that after optimization,the CFRP assembly can greatly reduce its weight without being lower the rigidity of the original steel assembly.The CFRP B-pillar Reinforced Plate was designed by layer.The three-point bending performance of assembly was validated by LS-DYNA software.The three-point bending performance of CFRP B-pillar was better than that of original metal assembly.A CFRP B-pillar Reinforced Plate sample was made and a three-point bend test was performed on the assembly to verify the accuracy of the finite element simulation results.Comparing with the actual vehicle crash test and vehicle side collision simulation results,the accuracy of the vehicle model established in this paper is verified.Analysis of the differences between the 2018 C-NCAP standard and the 2015 version of the new car collision,using the new side impact standard simulation to verify the CFRP B-pillar Reinforced Plate to improve the intrusion and intrusion speed of the vehicle side collision results,which is beneficial to the driver protection.The CFRP B-pillar assembly with topology optimization,size optimization,and ply optimization has achieved the goal of reducing the weight while ensuring the structural strength and rigidity.The purpose of lightweight design is achieved,which provides important guidance and reference for the application of CFRP on body structure parts.