A systematic approach for modeling multi-physics systems

Abstract

An engineering system may consist of several different types of components, belonging to such physical “domains” as mechanical, electrical, fluid, and thermal. It is termed a multi-domain (or multi-physics) system. In developing an analytical model of a multi-physics system, it is advantageous to use “unified” and “integrated” procedures for formulating different physical domains while including inter-domain dynamic interactions, in a systematic manner that will lead to a “unique” (single) model having physically meaningful variables. Such a model formulation is the focus of the present paper. In this context, a generalized method to incorporate impedance (e.g., the analogous use of mobility in the mechanical domain), exporting the modeling procedures from one domain into a different domain, conversion of a system in one domain into another domain, and realization of an equivalent single-domain model for a multi-domain system are addressed. This knowledge is useful in education, research, and application of multi-physics models of engineering dynamic systems. Illustrative examples are provided to clarify the presented approaches. This paper assumes a knowledge in linear graphs and some background material, as presented in the prior work of the author. The relevant nomenclature is listed at the end of the paper.