Air Leaking Effect in Winding on In-Roll Stress Analysis of Wound Roll(Machine Elements, Design and Manufacturing)

Abstract

A winding model for prediction of in-roll stress, considering air leaking effect is presented. Air layer is formed between webs within wound roll due to air entrainment, and then the thickness varies with air leakage of the widthwise edges and radial stress change while winding. It alters the stress with reducing apparent roll stiffness. In this study, the winding model is based on the assumption that the roll is a series of concentric tensioned hoops which are considered as equivalent layer of web and air layer. On estimating the air layer thickness, the air flow between webs is assumed as an incompressible squeeze flow between parallel plates in axial direction of the roll. In addition, it is extended to take into account that the stress at the already-wound part of the roll is sequentially varied from continuous web winding. Experimental validation result states that predicted value corresponds well to the experimental value amongst a wide range of the processing conditions, winding velocity, winding tension and web width. Furthermore, web width range of application on the winding model is investigated by a parametric study.