Spatial Joint Constraints in Flexible Multibody Systems Using the Absolute Nodal Coordinate Formulation

This paper is concerned with the formulation and computer implementation of spatial joint constraints and generalized forces using the large deformation absolute nodal coordinate formulation. Unlike the floating frame of reference formulation that employs a mixed set of absolute reference and local elastic coordinates, in the absolute nodal coordinate formulation, global displacement and slope coordinates are used. The nonlinear kinematic constraint equations and generalized force expressions are expressed in terms of the absolute global displacements and slopes. In particular, a new formulation for the sliding joint between two very flexible bodies is developed. A contact parameter is introduced as an additional new variable in order to facilitate the formulation of this sliding joint. Numerical examples are presented in order to demonstrate the use of the formulations developed in the paper.