Dynamic Impact Test And Simulation Of CFRP Joint In Vehicle B-pillar

The birth of vehicles brings convenience to people's life,but at the same time,it also brings an increasing consumption of fossil fuel,and result in a series of environmental problems.Energy saving and emission reduction have become the new direction in automobile industry,which drives carmakers to design and make lighter automobiles.It is well known that the use of lightweight materials is very effective in reducing vehicle emissions.Carbon Fiber Reinforced Plastics?CFRP?have many advantages such as high specific strength and stiffness,and excellent energy absorption among other composite materials.In addition,Carbon Fiber Reinforced Thermoplastic plastics?CFRTP?have the advantages of high toughness,short forming cycle and reusability.This material is used to manufacture the specimen in this study.Besides lightweight of automobile,we should also pay attention to the vehicle safety.According to vehicle accidents analysis,there are 4 kinds of impact mode,classified as frontal crash,side impact,rear impact and roll.This paper mainly considers the side impact condition in automobile collision.In the side impact condition,the side structure has weaker deformation endurance and energy absorbing ability,which could do harm to drivers.Therefore,this paper uses B-pillar joint made of CFRTP in order to design lighter and safer automobile.Firstly,the material deformation occurring in automobile collision is a high strain process,of which the strain rate distributes between 10^-110³/s.Therefore,a particular test fixture was designed and manufactured to obtain the material properties in dynamic condition.Tensile,compression,and shear tests were performed on the CFRTP laminate for the material characterization.Secondly,specimens for mechanical properties test and composite joints were manufactured by pressure molding process.The upper and lower panels were bonded by two kinds of connection modes,namely adhesive bonding and rivet bonding.Dynamic impact tests were carried out on joints using three different velocities namely 3.5,4.5,5.5 m/s.The load-displacement data at loading point were acquired and recorded.The key mechanical properties of the structure,such as collision X and peak load F,were obtained.The effects of failure modes on joint structural properties were identified and analyzed.Finally,the dynamic impact test of joint was simulated by finite element method.The above data were applied to simulation to analyze the fitting degree between simulation and experiment.Then,the simulation and comparison of thermoplastic and thermosetting CFRP B-pillar joints were carried out from the aspects of peak impact force,joint collision and specific energy absorption.And the advantages and disadvantages of the two materials were analyzed.The research shows that the CFRTP joint can reduce the vehicle body weight.It is lighter in weight than using metal materials and thermosetting CFRP.And it has lower impact peak force and larger energy absorption,but larger intrusion.