Study On Energy Absorption Characteristics Of Thin Walled Steel Pipe Based On Spiral Variable Strength Design

As a kind of traditional energy absorption component,thin walled tube has the characteristics of simple fabrication,low cost,good energy absorption and easy replacement.It is widely used in automobile,ship,spaceflight and other fields.When the collision occurs,the thin walled tube can absorb the impact energy and protect the occupant from injury.Starting from the microcosmic of material,the spiral variable strength thin wall steel pipe is prepared by the method of resistance heating and rapid cooling for 22 Mn B5 steel tube.The mechanical properties of the material after heat treatment were obtained by tensile test.The energy absorption characteristics of helical variable strength steel tube are studied by finite element simulation.The optimized variable strength tube is applied to the energy absorbing box of the vehicle anti-collision beam,and its influence on the impact energy absorption of the whole vehicle is analyzed.Firstly,the thin walled tube is treated by heat treatment with the appropriate technology,and the spiral variable strength steel pipe is prepared.The microstructure of the round tube was observed by means of metallographic microscope,and the morphological change of the microstructure in different regions was analyzed.The mechanical properties of the material were obtained by tensile test.In the finite element simulation software HyperMesh,quasi static and dynamic axial compression simulation analysis of the same size of the original steel tube and the spiral variable strength thin walled steel tube are carried out.By analyzing the deformation mode,load time curve and energy absorption index,the energy absorption characteristics of two kinds of tubes under two axial compression conditions are compared.It is found that the spiral variable strength tube has better energy absorption performance.Orthogonal test and variance analysis were used to optimize the design parameters of spiral variable strength thin wall steel tube.The design variables were chosen as the ratio of the original tissue area to the high strength zone,the width of the high strength zone and the wall thickness of the tube.The optimization design is carried out with specific energy absorption and crash force efficiency as optimization targets.The optimum design scheme of spiral variable strength round tube is obtained.The spiral type variable strength steel pipe is installed at the front end of the longitudinal beam of the vehicle to replace the energy absorption box designed by the original model as the main energy absorbing part in the collision process.The 50km/h frontal crash simulation analysis of the vehicle was carried out by using HyperMesh and LS-DYNA software.Through the analysis of the impact acceleration,the energy absorption of the circular tube and the transmission of the impact force,the energy absorption characteristics of the spiral variable strength round tube are better than that of the original tube.It is proved that the spiral variable strength steel tube designed in this paper can be applied to the whole vehicle impact energy absorption structure.