Thermodynamic Bond Graphs and the Problem of Thermal Inertance

It is shown that an isolated thermal inertance does not obey the second law of thermodynamics. Consequently, such an element should not be used in physical systems theory. To eliminate the structural gap in the thermal domain of current physical systems theory, a new framework is introduced using Bond Graph concepts. These Thermodynamic Bond Graphs are the result of synthesis of methods used in thermodynamics and in mechanics

Decomposition of multiport elements in a revised multibond graph notation

Decomposition rules are derived for multiport-transformers, -resistors, -storage elements and -gyrators into 1- and 2-port elements, junctions and bonds. It appears that it is useful to extend the vectorbond, or rather multibond, notation recently proposed by the author with a “multibond array”. Canonical forms are introduced on the basis of minimal realization, because decompositions of multiport elements are not unique. A new type of coupling factor (“directed coupling factor”) is introduced for multiport-resistors and capacitors

Parameter Variation of a Surface Acoustic Wave Motor

This paper investigates the influence of parameter variation on the behavior of a Surface Acoustic Wave (SAW) motor. To this end, a model of the motor is used to vary the parameters independently. This model indicates that an increase of the friction coefficient, the Young modulus and the radius of the spheres at the bottom of the slider gives a raise in both the velocity and traction force

MAX: a mechatronic model building environment

Abstract: A description is given of the state of the art and the functionality of MAX, an expert system for supporting conceptual design of mechatronic systems. Three model building principles are combined in MAX: – embedding equations in networks: a tight coupling between the graphical model formulation and the underlying equations assists the user in model building and evaluation. – multiple model formulations: one system can be manipulated and inspected simultaneously in multiple formulations (languages). – polymorphic modelling: a submodel definition is divided into a type that defines essential properties, and a specification that defines incidental properties. One type generally has multiple specifications, and types are organised hierarchically inside the library. By means of a simple case study, the utility of these principles is demonstrated. It is shown that MAX is a powerful model building environment that is well adapted to usage by designers.