Composite materials in flexible multibody systems

Abstract

In this work the flexible multibody dynamics formulations of complex models are extended to include elastic components made of laminated composite materials. The only limitation for the deformation of a structural member is that it must be elastic and linear when described in a body fixed frame. A finite element model for each flexible body is obtained such that the nodal coordinates are described with respect to the body fixed frame and the inertia terms involved in the mass matrix and gyroscopic force vector use a diagonalized mass description of the inertia terms. The coupling between the flexible body deformation and its rigid body motion is described using only standard finite element parameters obtained with a commercial finite element code. These elements include composite material shells and beams. For composite material beam elements, the properties of their sections are found using an asymptotic procedure proposed by Hodges. The component mode synthesis is used to reduce the number of generalized coordinates to a reasonable dimension for complex shaped structural models of flexible bodies. The kinematic constraints between the different system components are introduced and the equations of motion of the flexible multibody system are solved using an augmented Lagrangean formulation. Finally, the methodology is applied to the analysis of the deployment of a synthetic aperture radar (SAR) Antenna and the results are discussed.