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In this study, the failure mechanism of laser welds in lap-shear specimens of a high strength low alloy (HSLA) steel under quasi-static loading conditions is examined based on the experimental and computational results. Optical micrographs of the welds in the specimens before tests were examined to understand the microstructure near the weld. A micrographic analysis of the failed welds in lap-shear specimens indicates a ductile necking/shear failure mechanism near the heat affected zone. Micro-hardness tests were conducted to provide an assessment of the mechanical properties of the joint area which has varying microstructure due to the welding process. A finite element analysis was also carried out to identify the effects of the weld geometry and different mechanical properties of the weld and heat affected zones on the failure mechanism. The results of the finite element analysis show that the geometry of the weld protrusion and the higher effective stress--plastic strain curves of the heat affected and weld zones result in the necking/shear failure of the load carrying sheet. The deformed shape of the finite element model near the weld matches well with that near a failed weld. A finite element analysis based on the Gurson yield function with consideration of void nucleation and growth was also carried out. The results of the finite element analysis indicate that the location of the material elements with the maximum void volume fraction matches well with that of the initiation of ductile fracture as observed in the experiments. [ABSTRACT FROM AUTHOR]

In this paper, analytical stress intensity factor solutions for similar and dissimilar spot welds in lap-shear specimens under pinned and clamped loading conditions are derived. Closed-form solutions for similar welds in lap-shear specimens of equal thickness under pinned and clamped loading conditions are derived to show explicitly the effects of the clamped edges on the stress intensity factor solutions. Finite element analyses are also employed to obtain the stress intensity factor solutions for similar and dissimilar spot welds in lap-shear specimens under pinned and clamped loading conditions. Both computational and analytical solutions indicate that the clamped loading reduces the stress intensity factor solutions for the given specimen geometries by up to 7% for similar welds and by about 20% for dissimilar magnesium/steel welds. [ABSTRACT FROM AUTHOR]

In this paper, macro homogenized material models are adopted to simulate an in-plane constrained punch indentation test of a small-scale lithium-ion battery module specimen. The macro material models are based on the compressive stress–strain curves obtained from representative volume element (RVE) module specimens under in-plane constrained compression tests. The ABAQUS implicit solver is used for simulation of the punch test. The hyperfoam and the crushable foam material models in ABAQUS are adopted to fit the nominal stress–strain curves of the module RVE specimens under in-plane constrained compression. The load–displacement responses and the deformation patterns of the module specimen from the finite element analyses of the punch test based on the hyperfoam and crushable foam material models compare fairly well with the experimental results. However, the initial yielding and the corresponding unloading of the load–displacement curves of the module specimen due to micro buckling could not be modeled distinctively by the macro homogenized models. The computational results show that the material models available in commercial finite element software can be used to reasonably model lithium-ion battery modules under non-uniform compression loading conditions. [ABSTRACT FROM AUTHOR]