The objective of this research project is to develop an improved understanding of the stresses and defects that occur when metal, paper, and polymer materials are manufactured and wound into large rolls or coils. The research approach has two tasks: developing a higher-order mathematical model for the state of stress within a wound roll, and conducting laboratory experiments to measure stresses and conditions for the onset of such failure modes as v-buckling, sag collapse, and starring. The research specifically addresses non-linear material characteristics, stress variations in the roll's radial and width-wise directions, viscoelastic properties, slippage due to loss of layer-to-layer friction, and such process improvements as tension scheduling and the design of packing rollers.
If successful, the results of this research project will improve the production of wide continuous sheets of metal, paper, and polymer materials, which are sometimes referred to as "webs." Because of high winding tension and complex material characteristics, wound rolls can become unstable, buckle, or even collapse entirely. The research will advance knowledge relating to the constitutive characteristics of web materials and rolls. The key sources of disturbances that drive the formation of defects in wound rolls will be identified. Potential applications of the work may include the manufacture of aluminum sheet stock used in beverage containers, and the production of polymer base films that are used in computer data cartridges. Industrial practitioners may be able to apply the findings to wind web materials in a manner that minimizes damage to the underlying roll, that decreases scrap rates, and that improves the quality of their product.
