Research On Characteristic And Simulation Methods Of Spot Welds In Car Body

Spot weld is the most widely used technology in the modern bodywork. The CAEtechnology based on finite element method is an important technology in automotivedesign changed from experience design to scientific design. While usinggeneral-purpose finite element analysis software carried on calculation of bodyanalysis, the body sheet metal is easy to be described using shell element withmembrane and bending effects, but the spot weld itself is not easy to simulate. For thebody connected whit thousands of distribution of the spot weld, the finite elementmodeling technology of spot weld structure is the key technology ensuring that thecalculations is correct and accuracy.This paper first introduces the status and development trends of weldingtechnology in the automobile manufacturing, and instructs the application andadvantages of spot welding in today ’s domestic automobile production process, andthen mainly analyze spot welding characteristics, spot weld failure, specific weldingbase metal properties, and compare the simulation accuracy of the simulation methodof several different spot welding. Finally robustness is analyzed on two common spotwelding simulation methods in DYNA (beam and solid) and then gets thecorresponding results.In the auto frontal crash simulation analysis, the structural integrity of the whitebody is very important, and white body is connected through spot welding, therefore,spot welding simulation method in car collision is very important, this paper throughthe Lap-shear, Coach-peel, U-tension three spot welding sample model analysis theprecision of several spot welding simulation methods, and concludes that the simulatedaccuracy of beam is close to that of solid, and from different perspectives, through thesimulation to the traditional Lap-shear model and the improved Lap-shear model beamcontrast research characteristic of beam spot welding unit and solid spot welding unit,analyzing how the robustness is about two kinds of different spot welding simulationmethod to the grid unit integral way and spot welding unit’s relative position to thegrid unit, finally it is validated through a mini car frontal crash test.The paper’s analysis showed that the robustness of the relative element integralway and spot welding spot welding simulation of two different grid cell location, aswell as a mini-car frontal crash test verification, the simulation of the solid solder joint simulation approach high precision, can effectively simulate the solder joint failure,has an important guiding role in the crash simulation in the early vehicle developmentprocess.