A systematic approach for modeling multi-physics systems

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 multiphysics 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 multiphysics 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.