Mechanics of a thin web wrapped helically about a turn bar
Abstract
The mechanics of the interactions between a flexible web and an externally pressurized air cushion is modeled. The web is wrapped around the porous cylindrical turn-bar at an oblique angle (helically). The turn-bar supplies pressurized air into the web/turn-bar clearance. The shell model used to represent the mechanics of the web is an extension of a previous model, and it allows the web to be wrapped around the cylinder in a helical fashion. The geometric relations are based on Rongen's work [1] and steady state equilibrium equations are developed based on the work of Muftu and Cole [2]. The fluid mechanics of the air in the web/turn-bar clearance is a two dimensional form of the incompressible Navier-Stokes equations averaged in the clearance direction and augmented by non-linear source terms. Contact between the web and the reverser, which is undesirable in a turn-bar application, is included in the model in order to enable the analysis of the limiting cases. This paper describes the theory. Case studies and design recommendations are presented.
Citation
Muftu, S. (2005, June). The mechanics of a thin web wrapped helically about a turn bar. Paper presented at the Eighth International Conference on Web Handling (IWEB), Stillwater, OK.