Study On The Mechanical Property And Crashworthiness Simulation Of The Tailor-welded Blanks

The tailor-welded blanks structure can decrease the fuel consumption andemission pollution. So the use of tailor-weld blank in the automotive lightweightdesign become more and more widely, The frontal longitudinal beam is a primary partfor energy absorption in the frontal crash. The energy absorption ability anddeformation mode of the frontal longitudinal beam can affect the vehicle accelerationresponse and the force transfer route in frontal impact. Therefore, this paper choosesthe tailor-welded blanks thin-walled box beam whose structure and the state of failureis similar to the frontal longitudinal beam as the study object. The mechanicalproperty and crashworthiness simulation technique of the tailor-welded blank hasbeen studied.Firstly, According to the DIC technique test and hardness test, the materialparameters of weld zone and two heat affected zones are obtained with the derivedtheoretical formula. Examples based on finite element simulation and experiments areused to verify the accuracy of this method in this paper, and the results show that therefined method is better than the traditional method.Then, a FE model of a box beam in sled crash test have been built. A hybrid weldline model has been built. And the accuracy of this model has been verified. To thetailor-welded blank with the same thickness and different materials, the shell model,the rigid links model, the beam model and the coincident nodes model have beenresearched, To the tailor-welded blank with the different thickness and differentmaterials, the solid model, rigid links model, the beam model and the two layersbeams model have been researched. The research results show that the shell modelsuit the tailor-welded blank with the same thickness and different materials, the twolayers beams model suit the tailor-welded blank with the different thickness anddifferent materials.Finally, the influence factors to the crashworthiness of the box beam in sledcrash test were analyzed in terms of the weld line location、the spot weld space andweld structure. The research results show that the weld line location is260mm、thespot weld space is40mm and weld structure, the crashworthiness of the box beam isbetter.In this investigation, a refined method to identify the material parameters of theweld line based on the DIC technique and hardness test is proposed. A hybrid weld line zone has been built. The weld line models with the same thickness and differentmaterials, The weld line models with the different thickness and different materialshave been researched. Finally, the influence factors to the simulation precision of thebox beam in sled crash test were analyzed. The results from this study are useful toimprove the quality of anality of analysis of the finite element simulation, and theinvestigation has a certain reference value for engineering analysis.