On the consistent formulation of torques in a rotationless framework for multibody dynamics

A rotationless formulation of flexible multibody dynamics in terms of natural coordinates is considered. Since natural coordinates do not comprise rotational parameters, the consistent formulation and numerical discretization of actuating torques becomes an issue. In particular, the straightforward time discretization of the forces conjugate to natural coordinates may lead to a significant violation of the balance law for angular momentum. The present work shows that the theory of Cosserat points paves the way for the consistent incorporation and discretization of actuating torques. The newly proposed method adds to the energy-momentum consistent numerical integration of flexible multibody dynamics.