Experimental And Simulation Analysis Of A Vehicle Body Beam Based On Fluid-structure Interaction Numerical Algorithm

Compared with the finished products of traditional stamping and welding technology,the finished products of hydraulic forming technology have the characteristics of overall light weight,strong stiffness and high strength.Therefore,the application of hydraulic forming technology in aerospace,automobile and other fields is becoming more and more extensive.Hydroforming technology of fluid-solid interaction is the nature of the problem,but the AUTOFORM,DYNAFORM hydroform simulation software,only in the process of simulation of tube wall applied uniformly distributed load,not real internal flow field characteristics of reaction tube billet,fluid-solid interaction and the use of numerical calculation method of the forming process of tube can be output flow field information,reflect the flow velocity,pressure attenuation,pressure fluctuations on the interaction relationship between the forming quality of tube billet.Therefore,compared with Dynaform and other software,MSC.Dytran software based on fluid-solid coupling numerical calculation method can reflect the actual forming situation more truly.In this paper,the hydroforming is studied based on the fluid-solid coupling numerical calculation method by combining experiment and simulation.First of all,the design and experimental platform,rectangular section tube hydroforming set of rectangular tube hydroforming experiments,then the DYNAFORM software,and the simulation results based on numerical calculation method to describe fluid-solid interaction of MSC.DYTRAN software simulation results with the experimental results,this paper compares and analyzes validation fluid-solid interaction model and numerical calculation method is correct and closeness;Then,for the analysis of different methods on the quality of the rectangular section tube forming rule,in the original hydraulic forming experiment platform to join the fluctuating pressure generation system,a pulse loading rectangular tube hydroforming experiments,compared to two kinds of loading mode,forming quality and discussed through the simulation analysis of parameters such as pulse amplitude,pulse frequency and pulse waveform on the quality of the rectangular section tube forming regularity;Finally,the finite element model of the vehicle body beam was established based on the fluid-solid coupling numerical calculation method.The boundary conditions were set,the forming parameters were calculated according to the theoretical formula,and the influences of forming pressure,loading mode,pulsating amplitude and pulsating waveform on the forming quality of the vehicle body beam were analyzed.The experimental and simulation results show that the wall thickness uniformity can be increased by appropriate pulsation frequency.Compared with the traditional loading method,the pulse loading can improve the wall thickness of the target pipe and the forming quality of the rectangular section pipe.The greater the pulsation amplitude is,the better the uniformity of tube thickness is.Under the pulsating loading mode,the longer the depressurization period is,the longer the pseudo-springback time of pipe fitting is,and the better the uniformity of pipe fitting wall thickness is.When the pressure value reaches 200 MPa,the molding of the body beam has been completed.As the pressure continues to increase,the wall thickness of the pipe fittings decreases.In the process of beam forming,the velocity in the tube will increase because of the bending deformation of the pipe fitting.Compared with traditional loading,pulsation loading can improve the thickness uniformity of the body beam and the forming quality of pipe fittings.This paper set up two sets of hydraulic forming experiment platform,and completed the rectangular tube hydroforming experiments,through the experiment and simulation,the results of fluid-solid interaction to verify the correctness of the numerical method,by comparison with two kinds of simulation software simulation results,verify the fluid-solid interaction based on the simulation results of the numerical calculation method is more close to reality,again based on the fluid-solid interaction based on numerical calculation method for the simulation analysis was carried out on the car body beam,for the practical application of automobile body beam hydroforming technology to provide the reference and guidance...