New Type of Second-Order Tetrahedral Edge Elements by Reducing Edge Variables for Quasi-Static Field Analysis

Second-order tetrahedral edge elements afford much better accuracy in magnetic field analysis compared with first-order elements. However, they often entail higher computational cost due to the higher number of unknowns, many of them being redundant. The partial tree-gauging approach eliminates only a portion of the redundant edge variables, often reducing the overall computational cost. In this paper, we propose a new partial tree-gauging approach in second-order tetrahedral edge elements by unifying the two edges on the sides of elements into one, resulting in a new type of second-order tetrahedral edge element. Using the proposed elements in the analysis of two linear quasi-static magnetic field problems reveal the superiority of the edge unification over the conventional partial tree gauging in term of computational load.