Structure Graphs: A New Approach for Interactive Computer Modelling of Multi-Energy Domain Systems

1982 ◽  
Vol 104 (2) ◽  
pp. 143-150 ◽  
Author(s):  
R. Liebner ◽  
F. Abdullah ◽  
L. Finkelstein
Keyword(s):  
Computer Modelling ◽  
Engineering System ◽  
Engineering Systems ◽  
Bond Graphs ◽  
Signal Flow Graphs ◽  
Lumped Parameter ◽  
Energy Domain ◽  
Interactive Modelling ◽  
Linear Graphs ◽  
Flow Graphs

A computer package MEDIEM (Multi-Energy Domain Interactive Element Modelling) has been developed and mounted on a minicomputer for the purpose of interactive modelling of multi-energy domain engineering systems. The basis of the package is a graphical language called “structure graphs” which allows the user to model the “structure” or essential features of a lumped parameter engineering system in close correspondence to a schematic. It is shown that structure graphs arise naturally when modelling is considered within an interactive computer-aided environment. The approach has certain advantages over those based on current techniques such as bond graphs, linear graphs, and signal flow graphs; the main ones being the ease of model construction and the ease of effecting model changes (both structural and parameter changes). The package will handle both linear and nonlinear systems. Some illustrative examples of the use of structure graphs are provided together with a detailed example of the use of MEDIEM for modelling a complex differential pressure transducer. Lastly some special causal problems reported in the bond graph literature are examined and shown not to exist when MEDIEM is used.

Direct Application of the Loop Rule to Bond Graphs

1972 ◽  
Vol 94 (3) ◽  
pp. 253-261 ◽  
Author(s):  
F. T. Brown
Keyword(s):  
Transfer Function ◽  
Direct Reduction ◽  
Direct Application ◽  
Constant Parameter ◽  
Signal Flow Graph ◽  
Bond Graphs ◽  
Flow Graph ◽  
Signal Flow ◽  
Signal Flow Graphs ◽  
Flow Graphs

The Shannon-Mason loop rule permits direct reduction of a linear constant-parameter signal flow graph to a transfer function. Signal flow graphs can be constructed from bond graphs or sets of equations. Application of the loop rule to the parent bond graphs, however, with the aid of certain rules, is shown to be quicker and less prone to error. Also, four invariant classes of bond graph meshes are distinguished, with implications in physical analogies and in computation.

Reflections on Engineering Systems and Bond Graphs

1993 ◽  
Vol 115 (2B) ◽  
pp. 242-251 ◽  
Author(s):  
R. C. Rosenberg
Keyword(s):  
Mechanical Engineer ◽  
Problem Solving ◽  
Large Scale ◽  
Bond Graph ◽  
Engineering System ◽  
Engineering Systems ◽  
Bond Graphs ◽  
Modern Engineering ◽  
Versatile Tool ◽  
Systems Simulation

An important aspect of modern engineering systems is their great diversity. Often they include interactions among different physical domains, contain control subsystems, and are large-scale and complex. The bond graph is a powerful and versatile tool that can help the engineer to design modern engineering systems. Three issues are explored from a bond graph perspective: modeling of engineering systems, simulation of their behavior, and teaching about engineering systems. It is the author’s observation that bond graph methodology is one of the most useful engineering system techniques available and belongs in the problem-solving tool kit of every mechanical engineer. This paper develops a rationale for this viewpoint both for readers familiar with bond graph methods and for readers to whom they are new.

The Dynamic Behaviour of Passively Compensated, Hydrostatic Journal Bearings with Various Numbers of Recesses

1976 ◽  
Vol 18 (6) ◽  
pp. 292-302 ◽  
Author(s):  
P. B. Davies
Keyword(s):  
Dynamic Behaviour ◽  
Damping Ratio ◽  
Equations Of Motion ◽  
Steady State Solution ◽  
Flow Equation ◽  
External Excitation ◽  
Signal Flow Graphs ◽  
Flow Compensation ◽  
Circular Functions ◽  
Flow Graphs

A previously established small-perturbation analysis is developed to express the unsteady-state continuity-of-flow equation for an isolated recess in a passively compensated, multirecess, hydrostatic journal bearing in terms of generalized co-ordinates. The concise form of this equation enables motion of the shaft about the concentric position to be described by equations which are derived in closed form for bearings with orifice, capillary or constant flow compensation and any number of recesses. These equations of motion, and hence the expressions for the receptances which describe the response of a bearing to external excitation, are shown to be of exactly the same form for all bearings of the type considered. Furthermore, the damping ratio and natural frequency in any particular case are determined by a single dynamic constant which is shown to be equal to a linear combination of circular functions and a limited number of coefficients which may be found explicitly by routine use of signal flow graphs. The results of the analysis, which is exact within the stated assumptions, are compared with those of other workers and the steady-state solution of the equations of motion is shown to give an expression for static stiffness which is useful for design purposes. Numerical values of the dynamic constant for bearings with between 3 and 20 recesses are given graphically.

Bond Graph Sign Conventions

1975 ◽  
Vol 97 (2) ◽  
pp. 184-188 ◽  
Author(s):  
A. S. Perelson
Keyword(s):  
Graph Model ◽  
Bond Graph ◽  
Equivalence Classes ◽  
Parameter System ◽  
Bond Graphs ◽  
Lumped Parameter ◽  
Oriented Object

The lack of arbitrariness in the choice of bond graph sign conventions is established. It is shown that an unoriented bond graph may have no unique meaning and that with certain choices of orientation a bond graph may not correspond to any lumped parameter system constructed from the same set of elements. Network interpretations of these two facts are given. Defining a bond graph as an oriented object leads to the consideration of equivalence classes of oriented bond graphs which represent the same system. It is also shown that only changes in the orientation of bonds connecting 0-junctions and 1-junctions can lead to changes in the observable properties of a bond graph model.

Signal-Flow Graphs and Random Signals

1957 ◽  
Vol 45 (1) ◽  
pp. 74-86 ◽  
Author(s):  
William Huggins
Keyword(s):  
Signal Flow ◽  
Signal Flow Graphs ◽  
Random Signals ◽  
Flow Graphs
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