An accelerated three-dimensional coupled electromagnetic-mechanical model for electromagnetic pulse forming

Abstract

Electromagnetic pulse technology (EMPT) is receiving growing attention from industry and academia in response to the rising demand for manufacturing with lightweight alloys. Further advances in this technology, however, relies to a large extent on the accuracy and efficiency of the computational models that can be used to provide insight to the fundamentals of the EMPT-based processes. This paper presents a multiphysics computational framework for efficient finite element simulation of these processes. A reduction coefficient, k, is proposed to account for the variation of the magnetic field intensity with both time (explicitly) and spatial distance (implicitly). Incorporation of the reduction coefficient allows for one-way coupling of the electromagnetic and mechanical domains, hence facilitating accurate and substantially efficient 3D numerical analysis of large domains and complex geometries, as compared to fully coupled electromagnetic-mechanical analysis. The reduction coefficient, modelled here as an explicit decaying exponential function of time, was validated and calibrated against the experimental results (final deformed geometry) obtained from a series of tube compression experiments. The paper also includes a discussion of the application of the model in evaluating high strain-rate constitutive properties of materials under complex loading conditions, which can be a basis for dynamic testing of metallic materials at the same time of processing.