Flexible multibody dynamics of an Afterburner-type fairground attraction

In this paper, a method to analyze flexible multibody systems is presented, based on the floating frame formulation and applied to the Afterburner. In this formulation a floating frame is fixed to the rigid body center of mass. The rigid body motions, which make the system highly nonlinear, are described by constraint equations in a global frame. While the flexible deformations are described in the local floating frame by a linear combination of mode shapes multiplied with flexible coordinates. Linear finite element models are made and reduced to the interface points using the Craig-Bampton method, resulting in a small amount of mode shapes. At the interface points are revolute joints positioned, which include large three-dimensional rotations. To overcome singularity problems a solution procedure is described using an update of the rotation matrices. The results of this model are validated using simulations.