Study On Crashworthiness Of 7003 Aluminium Alloy

Automotive thin-walled components are the basic compoments of the car body,in the car crash safety as the main energy-absorbing ompoments.The low-speed frontal collision is the most frequent accident in the city's passive safety accident.The bumper is the main bearing and energy absobing component in the low speed fronal collision process,The thin-walled beam is the main part of the bumper,and the perfoemance of the thin-walled beam directly affect the integrity of other parts of the vehicle in the lowspeed collision.Based on the 7003 aluminum alloy material test,7003 aluminum alloy thin-walled tube was used as the research object,and the mechanical properies of the material under static and dynamic impact were studied by means of finite element simulation software and the mchanical properties were characterized.And the deformation and bearing perfomance of the thin-walled tube were tested and simulated.Finally,the low-speed frontal collision performance of different cross-sectional beam bumper is analyzed and selected.The main contents and conclusions of this paper are as follows:Firstly,the static and dynamic mechanical tests of 7003 aluminum alloy were carried out,and the stress-strain curves and fracture properties of the material were obained.The basic mechanical properties of 7003 alumium alloy were obtained by plate tensile test.The equivalent fracture toughness and tensile strength were changed with the notched radius of the gap.The dynamic tensile test of different strain rates showed that the weak strain rate sensitivity of the material and the linear relationship between the tensile strength and the equivalent plastic fracture strain and the strain rate logatithm.Secondly,the mechanical properties were described by the Johnson-Cook material model and failure model.The finite element simulations were carried out to simulate experiments of different stress states and strain rates.A comparison of the results obtained from the finite element method(FEM)simulations and experiments shows good agreement which proves the correctness of the finite element model and the constitutive relation.This approach of simulation is proved to be practicable in different stress states and different strain rates.Thirdly,the correctness of the material characterization,damage model and simulaion method is further verified by quasi-static three-point bending test and finite element simulation of aluminum alloy thin-walled tube.At the same time,the influence of the deformation mode and the bearing capacity of the thin-walled pipe is analyzed,and the reference design is put forward for the practical application and simulation analysis of the sructural design of the aluminum alloy thin-walled tube.Finally,the mechanical performance parameters of 7003 aluminum alloy are applied to the 20KM/h low speed frontal crash simulation analysis of automobile front bumper.The collision performnce of different cross-section beams is analyzed by deformation mode and energy absorption performnce,and as the reference for the beam design and application of materials.To sum up,this paper focuses on the deformation,load and energy absorption characteristics of 7003 aluminum alloy thin-walled parts during the collision,the static mechanical properties of marerials under diferent stress stetes and the dynamic mechanical properities under different strain rates were studied.The constitutive and fracture aging models which can characterize the mechanical properties of the materials and validated.The deformation mode and the bearing capacity of the thin-walled tube.Finally,it is applied o the low-speed frontal collision simulation analysis of the cross-section beam with different cross-sectional shapes.This paper provide reference for the safety design and calculation of 7003 aluminum alloy thin parts.