| In recent years,with the rapid development of social economy,people travel more convenient,and travel frequency of vehicles such as cars is getting higher and higher.Tailor rolled tubes,as energy absorbers,are usually installed on vehicles such as automobiles,ships and airplanes.In case of collision,they can absorb collision energy by their own crushing deformation to reduce damage to vehicles and protect passengers.However,the thickness and strength of material in traditional tailor rolled tubes are usually selected according to the maximum load,so that the material thickness and strength in non-maximum load area is still relatively rich.Therefore,in view of the existing situation that the mechanical properties of the new variable wall thickness tailor rolled tube vary with thickness,but the mechanical properties and thickness changes as well as the response relationship between heat treatment processes have not yet been theoretically formed,the following research has been carried out in this paper:(1)The data before and after mechanical properties annealing in different thickness zones of cold rolled differential thickness plate were obtained by unidirectional tensile test.The variation trend of mechanical properties anisotropy in different thickness zones of differential thickness plate before and after annealing was obtained,and the mechanical properties distribution and evolution rule of differential thickness plate before and after annealing were systematically studied.Quantitative relationship description model of annealing process-thickness-Mechanical Properties of cold rolled differential thickness plate was established.(2)By means of metallographic observation,grain size,grain boundary orientation difference,tensile fracture analysis and dislocation density analysis,the evolution mechanism of differential thick plate structure before and after annealing is explored.(3)Finite element model of axial crushing of tailor rolled tube with variable wall thickness is established.The crushing simulation of tailor rolled tube with variable wall thickness and different structures is carried out and the effect of axial crushing energy absorption is comprehensively evaluated.Guidance for optimizing the design of thickness and performance distribution of tailor rolled tube is given.Based on the study of mechanical properties and microstructure evolution mechanism of cold rolled differential thickness plate with annealing process,the mechanical properties and axial crushing behavior of variable wall thickness tailor rolled tube under annealing process are deeply studied by combining experiment and simulation,which provides theoretical guidance for thickness and mechanical properties control mechanism of variable wall thickness tailor rolled tube. |
