C.L. Bottasso, M.
Borri, L. Trainelli
Geometric
Invariance
Computational Mechanics, 29:
163-169 (2002).
Abstract
We discuss changes of variables deriving from changes
in the placement of reference entities in the modeling of rigid bodies, beams
and shells. We show that standard numerical procedures in general fail to be
invariant with respect to these particular changes of variables, and we
characterize the nature of the error. Finally, we show how the fixed pole form
of the equations of equilibrium automatically guarantees invariant numerical
processes, being based on global kinematic and co-kinematic quantities.