The concept of energy in the analysis of system dynamics models

摘要

This paper applies for the first time the Newtonian concept of energy to stock-flow systems and employs it to relate system behaviour to model structure. Kinetic energy and work done are defined analytically using the concepts of loop impact and force from the Newtonian Interpretative Framework and are examined numerically within system dynamics simulations. The energy analogy is used to analyse models by understanding how loops of different orders and types act as energy sources, sinks and exchange, using the system dynamics equivalent of the work-energy theorem. It is shown that energy describes the cumulative effects of feedback on stock behaviour, in contrast to the instantaneous description given by existing methods of loop dominance. This approach gives additional insight over that of existing dominance methods, capturing the dynamical influence of loops even when not dominant. The analogy's explanatory power provides quantitative and informal analysis. (c) 2022 The Authors. System Dynamics Review published by John Wiley & Sons Ltd on behalf of System Dynamics Society.