Spotweld Models for Advanced High Strength Steels


Spot Weld Element

We have developed an initial version of the Spot Weld Element (SWE) modeling framework and demonstrated the effectiveness of the proposed modeling approach. This development phase considered two Advanced High Strength Steel (AHSS) grades and one gauge thickness. The constitutive models used in the SWE incorporated microstructural changes in the weld region of AHSS that were obtained using an integrated electrical-thermal-mechanical-microstructural resistance spot welding model and validated by weld microstructure characterization. One of the main objectives of the project was to base the failure criteria in the spot weld on intrinsic material properties, and relate them to the underlying material microstructure. For this phase we have implemented a simple criterion based on equivalence of the strain energy to failure. To properly account for changes of AHSS mechanical properties in spot welding process, more detailed material deformation and failure models will be needed, but even with the current, relatively crude approach, the simulations yield very satisfactory results.

Future research is planned to consider wider range of materials, thickness ranges, and various welding/joining issues. Treatment of failure and fracture, microstructure-informed material mechanical response, and thermo-mechanics process models will be addressed to further refine and improve the efficiency and accuracy of the SWE formulation.