Research On The Structure Design And Energy Absorption Characteristic Of Hat-section Beam Under Axial Loading

With the rapid development of the modern automobile industry,the automobile safety has been paid great attention by people,especially the frontal crash is the focus of attention.The kinetic energy of frontal impact was dissipated through plastic deformation,fracture and other modes,and automobile front rail is the main energy absorbing component.Therefore,the axial beam'senergy absorption characteristicswill directly affect the vehicle collision safety.In this paper,the theoretical analysis,simulation test and dynamic impact test were investigated to studies the behaviors of hat-sections under axial crushing.Deformation mode and failure form were analyzed,and puts forward corresponding solutions to improving energy absorption efficiency of front longitudinal beam.In this paper,the angle between two sides,the width of the weld edge,the position of the weld joint,the inner strengthening of hat-section were carefully studied.What's more,the weight of the structure was taking into account.According to the above problems,this article carries out researches as follows:(1)The failure of the welded hat-section under axial compression is presented and analyzed.Processes of absorbing energy during crushing deformation and structural design factors were theoretically analyzed.The welded super-folding element(WSFE)is proposed in this article for the first time,on the basis of traditional super-folding element(SFE)and structurecharacteristics of thin-walled beams.By comparing and analyzing the difference between the traditional super-folding element and the welded super-folding element,the causes of invagination,the welding spot tearing and the local bending are found.At last,the corresponding improvement methods are put forward.(2)Study the influence of structural parameters on crushing characteristic of hat-section by numerical method.The influences of the angle between two sides,the width of weld edge and the position of the weld joint on the energy absorption characteristics were analyzed.The results show that these design elements have great influence on energy absorption of hat-section beam.(3)Analyze the crushing characteristics of top-hat and double-hat sections with various constructionsby dynamic impact test.The experimental results show that the angle of the adjacent two sides has no obvious effect on section force,but the structural failurewas improved observably;The width of weld edge has a great influence on the section force for double-hat,and section force is positively related to the width of the weld edge;The influence of the position of the solder joint on deformation form is greater than that of section force;It provides an effective method to solve the failure phenomenon by changing the width of the weld edge and changing the position of the solder joint;The inner strengthening greatly enhanced the section crushing force and improved the deformation.The results show that internal reinforcing plate can improve the efficiency of energy absorption while improve the stability of the structure.At last,the dynamic impact test results verify the correctness of the simulation rules.