Supercritical stability and bifurcations in axially moving web

Dynamic stability and bifurcations in axially moving web have been investigated. To analyse supercritical dynamic behaviour of the thin web the beam model is considered. A general velocity proportional damping force is added to the non-linear governing equation. Approximate solution of the partial differential equation of motion is obtained using the Galerkin method. The investigation procedure follows that derived from the Hopf bifurcation theory by looss and Joseph and consists in seeking approximate periodic solutions of non-linear equations of the web motion in a parametric form. The moving web may encounter divergent or flutter instability at supercritical transport speeds. The attention is focused on free vibrations in the neighbourhood of some points on the stability boundary in the flutter region of the linearized system. The Hopf bifurcation kind (sub- and supercritical) has been investigated at these points.