By combining linear graph theory with the principle of virtual work, a dyna
mic formulation is obtained that extends graph-theoretic modelling methods
to the analysis of flexible multibody systems. The system is represented by
a linear graph, in which nodes represent reference frames on rigid and fle
xible bodies, and edges represent components that connect these frames. By
selecting a spanning tree for the graph, the analyst can choose the set of
coordinates appearing in the final system of equations. This set can includ
e absolute, joint, or elastic coordinates, or some combination thereof. If
desired, all non-working constraint forces and torques can be automatically
eliminated from the dynamic equations by exploiting the properties of virt
ual work. The formulation has been implemented in a computer program, DynaF
lex, that generates the equations of motion in symbolic form. Three example
s are presented to demonstrate the application of the formulation, and to v
alidate the symbolic computer implementation.