M. Borri, C.L.
Bottasso, L. Trainelli
An
Invariant-Preserving Approach to Robust Finite-Element Multibody Simulation
Zeitschrift für Angewandte Mathematik und Mechanik, 83 (10):
663-676 (2003).
Abstract
We briefly describe the main concepts that have
inspired a novel approach for the integration of general non-linear structural
and multibody dynamics problems within a finite-element framework that includes
geometrically exact beams. In this
approach, a numerically robust family of second to fourth order accurate
algorithms are devised, which retain several important qualitative features of
the exact solution. Among these, we address frame indifference, invariance with
respect to reference entities (such as beam axes and shell mid-surfaces), and,
for load-free motions, preservation of the system total linear and fixed-pole
angular momenta and a rigorous bound on the system total mechanical energy.
When constrained systems are analyzed, these results are obtained by
additionally requiring at the discrete level the preservation of Newton's Third
Law of Action and Reaction and the vanishing of the work of the reaction forces
for each constrained body pair. As a result, the schemes exhibit full
non-linear unconditional stability according to the Energy Method. The
underlying single-step, two-stage, implicit difference schemes provide tunable
high-frequency damping ranging from null ($\rho_{\infty}=1$) to asymptotic
annihilation ($\rho_{\infty}=0$). The scheme performances are shown to improve
on those provided by widely adopted algorithms stemmed from the Newmark family
such as the generalized-$\alpha$ methods. Representative numerical exercises
are included to illustrate the main features of the methodology.