Product Development and Finite Element Analysis of Polyurethane Press Shoe : Produktutveckling och finit element analys av press-sko i polyuretan

Abstract: The press-section of a paper machine holds several different types of press rolls. One of the many press roll variants is the Valmet produced press roll, ViscoNip. This press roll utilizes an extended nip in order to increase the amount of water removed. The extended press nip in ViscoNip is special since it is controllable by a pressurized polyurethane press shoe. The press shoe runs through the body of the press roll. Due to limits of the current production process, new manufacturing methods and construction solutions are needed. In cooperation with another thesis, the current design and manufacturing process was reviewed and a plan intended to improve the current solution was formulated. The plan was to, by working together in a project, perform a product development process intended to create concepts able to utilize new methods of manufacturing. By using established methods of concept generation, such as Brainwriting 6-3-5, 11 concepts were created. Some of these concepts involved a redesign of the press shoe, leading to a need for construction and performance analysis. With the other thesis focusing on researching new possible and available manufacturing solutions. The work of this thesis fully committed to the structural and mechanical performance evaluation of the new concepts. This was performed by creating a model of the technical application using Finite Element Modelling in ABAQUS. The model included a hyperelastic material model for the polyurethane material as well as cohesive zone modelling to account for partitioning of the part. The model was then used to simulate the different concepts as they were subjected to a challenging load case. The results of which were used as the basis for structural and performance analysis. The analysis showed proof of sufficient structural stability and mechanical performance for all evaluated concepts. Then, in cooperation with the other thesis, a final concept choice was made. All in all, three different redesigned concepts were deemed as having potential for further development. The current solution was also deemed as having potential for future development but only when new manufacturing methods or techniques were considered.