ON THE TRANSVERSAL VIBRATIONS OF AN AXIALLY MOVING CONTINUUM WITH A TIME-VARYING VELOCITY: TRANSIENT FROM STRING TO BEAM BEHAVIOR

摘要

In this paper an initial-boundary value problem for a linear equation describing an axially moving stretched beam will be considered. The velocity of the beam is assumed to be time-varying, since the order of magnitude of the bending stiffness terms depends on the vibrations modes and the frequencies involved a that combination of two simplified models (a string equation and a beam with string effect equation) will be used to describe the transversal vibrations of the system accurately. Based on the calculations of the natural frequencies the regions of applicability of these models will be determined. A two time-scales perturbation method will be used to construct formal asymptotic approximations of the solutions. It will be shown that the linear axially moving "string to beam" model already has complicated dynamical behavior.