On the role of frame-invariance in structural mechanics models at finite rotations

in this work we re-examine so called geometrically exact models for structures, such as beams, shells or solids with independent rotation field, with respect to invariance under superposed rigid body motion. A special attention is given to clarifying the issues pertaining to the finite element implementation which guarantees that the invariance of the continuum problem is preserved by its discrete approximation. Several numerical simulations dealing with finite rotations of structural models are presented in order to further illustrate and confirm the given theoretical considerations. (C) 2002 Elsevier Science B.V. All rights reserved.