Basic Mechanical Properties Analysis Of Ultra Hight Strength Steel Welding Stracture

In recent years, due to higher oil prices and environmental protection, vehicleweight reduction has become a new development trend. To reduce the car’s weight,many cars are make from lightweight and high-strength steel. In order to meet therequirements of the static strength and other properties, the use of high-strengthlightweight materials, requires higher welding technology. Spot weld structures arewidely used in automobile making, whose connectivity has a great effect onsubsequent processes. However, due to the higher strength of ultra high strength steel,the mechanical properties of the spot weld structure are different from commoncarbon steel, thus it is necessary to research and analyzed strength and othermechanical properties of the steel, and optimizes some dimension parameters toimprove the efficient of the material.(1) Tensile experiment of ultra high strength steel welding sample wasperformed, meanwhile pasted strain gage, and studied the process of stresses whenforce was loaded, and samples was optical photographed, analyzed the characteristicsof material. Measure the hardness values around the weld spot by the Vickershardness are measured, analyzed varies of material properties, and provided thematerial parameters for the subsequent numerical simulation.(2) Simulation of ultra high strength steel welding structure was performed byANSYS, the strain results obtained by the simulation with the experimental resultswere compared to verify the validity of the simulation, which made foundation for theother simulation analysis.(3) Analyzed the weaknesses of the structure by the stress field distribution ofsimulation, and approximatively derived the corresponding relations between ultimatestrength of tension at weak and load, by which could estimated the strength facilitate;The effect on the stress distribution by spot radius etc parameters of the structural wasresearched, to prepare for subsequent optimization.(4) Though APDL language of ANSYS, established simulation model byparameters. Minimum volume of the structure as object, chooses the half of length ofoverlap and thickness as design variables, and the ultimate strength of the weaknesses as a constraint, and used response surface method to establish explicitly the constraintfunction, the optimization model was established and solved by using sequentialquadratic programming algorithm, the entire optimization process was programmedby C language was, to obtain the optimal value of overlapping length and thicknessautomatically.