An Approach for Eddy-Current Calculation in Railguns Based on the Finite-Element Method

This paper presents a global method of evaluating nodal eddy currents based on the known nodal potentials, which is a Galerkin finite-element method formed by employing the Schaubert-Wilton-Glisson basis function as a weighting function. As a result, the accuracy of eddy-current evaluation in the railgun computation could be increased using the nodal finite-element method. The new method takes all the nodal potential values into account to obtain the global nodal current density directly by solving the finite-element equation, which could overcome the drawback of the traditional local element postprocessing method. The computational results show that the new method could greatly enhance the computational accuracy of eddy current, relative to the traditional element postprocessing method. This method could not only be used in the eddy-current evaluation of the railgun but also in other gradient field computations based on known nodal potential values.