Mechanics of a cylindrical flexible web floating over an air-reverser

The mechanics of the fluid/structure interaction between a thin flexible web, wrapped around a cylindrical drum (reverser), and the air cushion formed by external pressurization through the holes of this drum is analyzed. The web deflections are modeled by a cylindrical shell theory that allows moderately large deflections. The airflow is modeled in two-dimensions with a modified form of the Navier-Stokes and mass balance equations, with non-linear source terms. The coupled fluid/structure system is solved numerically. The mechanics of the interaction between the web deflections and the air cushion generated by the reverser is explained. The effects of the problem parameters on the overall equilibrium are presented

Experimental and theoretical study of web traction over a nonvented roller

The traction developed between a thin flexible web, wrapped around a nonvented, rotating cylindrical roller is studied experimentally and theoretically. A series of eight webs representing a wide range of surface roughness characteristics are traction tested against the same roller over a wide speed range. A one-dimensional finite difference model that couples air film pressure (Reynold's equation), web bending and solid-body contact using an asperity compliance function is used to model the experimental traction data. An optimization technique is used to estimate the asperity compliance function parameters. A new model for computing the asperity engagement height for non-Gaussian surfaces is presented when the roughness of both surfaces is taken into account. Results are presented which indicate the viability and utility of the new methods