| Nowadays, the growing popularity of the automotive has increased the problemsof environmental pollution and energy consumption, pursuit of the AutomotiveLightweight becomes more popular than ever to reach the energy conservation andenvironmental protection requirements. Resistance spot welding is widely used inautomotive body welding, and the fatigue performance of the spot-welded structure isan important factor to evaluate the quality of the car, also directly affects theoperational safety and reliability of the automotive during the using life. Because ofthe excellent weight reduction performance, the hot stamping high strengthsteel(HSHSS)22MnB5, which is one of the most intensity level in the ultra-highstrength steel, was widely used in the body structure. In addition, there are somedifferences between HSHSS and ordinary steel, such as the spot welding process, aswell as the fatigue performance of the spot-welded structure. So we need to makesome research on the spot welding fatigue behavior of this new material.In this paper, two methods containing experiment and numerical simulation wereadopted to analysis the fatigue performance of the tensile-shear spot-welded structureof hot stamping ultra-high strength steel, the study includes the following aspects:(1) Fatigue experiment of spot welding sample is tested by using group fatiguemethod, some fatigue performance comparison research and analysis was carried onin aspects of different welding process and different base metal, samples made bythree different welding process parameters and CORLSW process were used to carry ona group fatigue testing under three different stress levels, the results were used to fitthe S-N curves and the p-S-N curves.(2) Numerical Simulation of ultra high strength steel welding structure isperformed by using ANSYS software and FE-SAFE software, the APDL in ANSYSwas used to establish the parametric model, equivalent structural stress method andnominal stress method were adopted to calculate the life of the welding structure, thewhole process is achieved by batch and macros.(3) Based on the effectiveness of the simulation model, some structural factorsaffecting the fatigue life of the whole structure were used to make assessment calculations, which will provide some theoretical reference for improvement of thestructure, and lay the foundation for the future optimization.(4) Fatigue analysis software of ultra-high-strength steel spot weldingtensile-shear structure was developed to engineering, nugget radius, the width ofheat-affected zone, plate thickness and the load magnitude can be entered to generatethe model, some related software were called to calculate the strength and the fatiguelife, the result can be displayed in the new software, all of these turns the outcomes inthis paper into practical application, and also bring many convenience to engineers. |
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