Single span web buckling due to roller imperfections in web process machinery
Abstract
Scope and Method of Study: To study instabilities in webs resulting from contact with imperfect rollers, whether in their geometry or their orientation in a web span. The instabilities covered include trough formation in web spans and wrinkling of webs on rollers. Webs are modeled as beams successfully, until trough form in the web spans. A buckling criterion for web in a free span is linked to various models to predict the formation of troughs in the web. In the case of web wrinkling, finite elements models using wrinkling membrane elements are used to simulate webs with developed troughs. These are linked to shell buckling criterion in order to predict webs wrinkling on rollers. Cases these techniques are applied to in a consistent manner are: misaligned rollers, tapered rollers, misaligned and tapered rollers, crowned rollers, and rollers with an enlarged section. Findings and Conclusions: Experimental verification is provided for comparison to all proposed models. It was found that the presence of troughs in a web does not affect the deflection in the case of tapered rollers. Simplified mass continuity is applicable to predict strains due to contoured rollers. In all cases studied troughs are required to allow wrinkles to form in webs.
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- OSU Dissertations [11222]