An extended modelling technique with generalized strains for flexible multibody systems

Abstract

A new method, which is an extension of a finite-element formulation, introduces generalized strains related to nodal coordinates by implicit equations, which can be treated as constraints. This formulation allows a larger freedom in developing elements, so it eases the building of elements with a higher accuracy. In many cases, this enables modelling flexible multibody systems with fewer elements and fewer degrees of freedom for a given accuracy or using more accurate models. Because the systems are modelled with coordinates and constraints, all familiar analysis techniques can be applied, such as simulation, calculation of static solutions, linearization and an input–output description. The method is tested for planar and spatial beam elements based on assumed strains. Some examples of large static deflection and dynamics are presented, which show the advantage over some existing element formulations.