Within engineering design, optimization often involves building models of w
orking systems to improve design objectives such as performance, reliabilit
y and cost. Bond graph models express systems in terms of energy flow and c
an be used to identify key factors that influence system behaviour. Robust
Engineering Design (RED) is a strategy for the optimization of systems thro
ugh experimentation and empirical modelling; however, experiments can often
be prohibitively expensive for large or complex systems. By using bond gra
phs as a front-end to RED, experiments on systems could be designed more ef
ficiently, reducing the number of experiments required for accurate empiric
al modelling. Two case study examples are given which show that bond graphs
can be used to good effect in the empirical analysis of engineering system
s. Copyright (C) 2000 John Wiley & Sons, Ltd.