Analysis of Spaghetti Problem Using Multibody Dynamics

Abstract

This paper presents a dynamic analysis method for “Spaghetti Problem” using Multibody Dynamics technique. When a flexible body such as the thin plate or the paper sheet is pulled into the gap of elastic wall, its free tip vibrates most frequently near the entrance of that area. This phenomenon is observed on the rolling mill and the copy machine, and is called ’’Spaghetti Problem”. The discrete beam model that is considered large rotation of bodies is assembled using rigid bodies connected with kinematically revolute joints and tortional springs and dampers that represents bending rigidity. The gap is modeled by the hard springs and dampers, on the assumption that it has the large rigidity in lateral direction, and suppresses the lateral displacement of the beam in it. The dynamic behavior of a thin plate is illustrated by numerical simulations with the presented method, and the dynamical characteristics of this phenomenon are examined by time history of total energy of the beam that is placed in outside of the wall. Moreover, the relation between driving velocities and magnitudes of their vibrations is investigated by its strain energy. © 1999, The Japan Society of Mechanical Engineers. All rights reserved.