EFFECTIVE METHOD FOR ANALYSIS OF ELECTROTHERMALLY COUPLED FIELDS

An effective method is presented for solving a nonlinear system of par tial differential equations that describe the time-dependent electroth ermally coupled fields for passage of constant electric current in a t hree-dimensional conductive medium. A numerical model of this physical phenomenon was obtained by the finite element method, which takes int o account the temperature-dependent characteristics describing the mat erial parameters and conditions of heat transmission outside of the an alyzed objects. These characteristics and conditions make the problem strongly nonlinear. The solution uses the Newton-Raphson method with t he appropriate procedure for determining the Jacobian matrix elements. The main idea of the proposed method is the use of an automatic time step selection algorithm to solve heat conduction equations. The influ ence of the assumed accuracy value on the final result of the nonlinea r calculation is discussed. The theoretical results were confirmed by the numerical experiments performed with selected physical objects. (C ) 1995 John Wiley & Sons, Inc.