No abstract

No abstract

Resistance spot welding (RSW) is widely employed in sheet metal fabrication, in particular in automotive bodies and structures. Manufacturers are increasingly demanding reduced design periods with improved safety requirements, which could potentially be achieved through computational simulations. This paper presents an integrated approach combining simulation of the welding process, materials characterisation and mechanical modelling to study the effect of welding parameters on the strength of spot-welded joints. The welding process was simulated and the dimensional attributes were used to build the mechanical models for strength analysis. The constitutive material properties of the base, nugget and the heat-affected-zone (HAZ) were determined by an inverse FE modelling approach using indentation test data. The predicted deformation of spot-welded joints of a typical automotive steel under tensile-shear load showed a good agreement with experimental results. The validated models were further used to predict effects of welding parameters on the strength and failure behaviour of weld joints. Potential uses of the approach in optimising welding parameters for strength were also discussed.

In this work first principle calculation is applied to establish systematic ground state elastic property data of three typical cubic binary monocarbides (TiC, VC and NbC). The bulk modulus, Young's modulus, shear modulus, and Poisson ' s ratio are determined from the Voigt-Reuss-Hill approximation method and compared with other published data. The micro Vickers hardness is also predicted, the hardness data is compared to published data. The anisotropy in elastic properties of the carbides is studied through calculating the universal elastic anisotropic index; percent anisotropy in compressibility and shear as well as the shear anisotropic factors on the specific crystal planes. A python program is developed to integrate first principle calculation in Materials Studio data and establish the directional anisotropy in elastic properties in 3D space and projection on key crystal planes. 3D constructions and plane projection of the elastic properties based on the maximum, minimum and averaged values approaches is used to present and compare the anisotropy feature of the carbides. The data for E, G and Poisson ' s ratio is comparatively analysed and discussed, and future direction in developing systematic data through physical modelling is discussed.