Simulation of wavy wrinkling of web caused by roller tilt (Change of the number of wrinkles and causes of the onset of the wrinkling)

Abstract

This paper deals with the onset and development of wavy wrinkling of a web caused by a roller tilt using a FEM commercial software. The simulation model mainly used is composed of two rigid rollers and a web (a rectangular sheet) divided by a membrane element with four nodes. After applying tension to the web, both end parts of the web are fixed to the rollers and then the one roller is inclined gradually. The main results are summarized as follows. (1) The wavy wrinkling suddenly occurs at a tilt angle β of the roller. A pitch, amplitude and slope of the wavy wrinkles are larger in the loose side of the web comparing with those in the tight side. The number of wavy wrinkles of the web decreases exponentially with increase in β. A slack area is approximately estimated as an area where the von Mises stress is smaller than a certain value. (2) The number of wavy wrinkles becomes larger when Young's modulus or a thickness of the web decreases, or when the web tension increases, comparing at the same β. (3) The onset of the wavy wrinkling is strongly affected by the imperfection of the tensile strain distribution and of the web position relative to the rollers in the tension process. (4) Another wavy wrinkling simulation method is proposed, which makes a membrane buckle by applying a small out-of-plane displacement.