Dynamics of Flexible Bodies Using Generalized Newton-Euler Equations

Abstract

A force acting on a rigid body produces a linear acceleration for the whole body together with an angular acceleration about its center of mass. This result is in fact Newton-Euler equations which are used as basis for developing many recursive formulations for open loop multibody systems consisting of interconnected rigid bodies. In this paper, generalized Newton-Euler equations are developed for deformable bodies that undergo large translational and rotational displacements. The configuration of the deformable body is identified using coupled sets of reference and elastic variables. The nonlinear generalized Newton-Euler equations are formulated in terms of a set of time invariant scalars and matrices that depend on the spatial coordinates as well as the assumed displacement field. A set of intermediate reference frames having no mass or inertia are introduced for the convenience of defining various joints between interconnected deformable bodies. The use of the obtained generalized Newton-Euler equations for developing recursive dynamic formulation for open loop deformable multibody systems containing revolute, prismatic and cylindrical joints is also discussed. The development presented in this paper demonstrates the complexities of the formulation and the difficulties encountered when the equations of motion are defined in the joint coordinate systems.