Shear in multispan web systems

Abstract

Wrinkling research has been concentrated in past years on understanding web wrinkling in isolated spans in web lines [1]. It is expected that some of the fundamentals which govern single span behavior will also apply to multispan wrinkling problems. For instance it has been found that predicting the shear in the web is necessary to be able to predict shear wrinkles, which are wrinkles due to roller misalignment. Earlier works Young[2] and Dobbs[3] have concentrated on determining shears and moments in moment transfer conditions where the coefficient of traction was assumed constant. It has also been found that knowledge of the traction capacity between webs and rollers allows the calculation a lower bound in web tension below which wrinkling becomes impossible. The focus of this paper is to show how shears in multispan web systems can be predicted. How these shears are impacted by the complications of traction capacities which vary as a function of entrained air and by web edge slackness will be treated.