Finite element analysis of winding nip mechanics

Abstract

Wound-on-Tension (WOT) is the tension in the outermost layer of a winding roll that is created due to the incoming web tension and the tension induced by the nip roller called Nip-Induced-Tension (NIT). This paper presents the analysis of the contact mechanics between the nip roller, incoming web layer and the winding roll and explains the development of wound-on-tension in a winding process. In order to understand the contact mechanics an explicit finite element formulation is employed. The results show that the surface tractions that exist in the top and the bottom surfaces of the incoming layer underneath the nip roller give rise to a net traction. The sum of the incoming web tension and the total traction which is calculated as the integrated value of the net traction over the contact width produces the wound-on-tension. The numerical results show that the NIT is equivalent in both center and surface winding.