The aim of this thesis was to investigate the difference between containerboard materials strength and stiffness properties in tension and compression, how the mechanisms behind compressive and tensile properties are affected by the relative humidity of the ambient air and how the relative humidity affects the compressive response of the fibre network. These properties are used to predict the lifetime performance of corrugated boxes and to prevent early collapses of the boxes and thereby waste or harm of the transported goods inside. The work also discusses the methods used to evaluate the different properties and how reliable the results are. The experimental part includes testing of linerboard and fluting materials from both virgin and recycled fibres, which have been conditioned at 50% and 90% relative humidity. The compression tests were filmed to evaluate if different compression failure modes can be related to the strength and stiffness of the material. The results indicated that the compressive strength and stiffness differ from the strength and stiffness values in tension at 90% relative humidity. Compressive strength is lower in both 50% and 90% relative humidity compared with the tensile strength. However, the compression stiffness shows a higher value than the tensile stiffness at 90% relative humidity. The study of the method for evaluating the compressive behaviour of the paper does not present a complete picture on what type of failure the paper actually experience.

Kraftliners är något som används till att skapa bland annat ytskiktet till pappersprodukten wellpapp. Wellpapp består av ett lager kraftliner på antigen en- eller vardera sidan av ett vågigt papper, kallat flute. På uppdrag av SCA R&D undersöker detta kandidatarbete möjligheten till att skapa en konceptuell prototyp till en maskin som kan konstruera wellpappsprover på deras laboratorium. Detta för att via tester kunna prediktera hur variationer i wellpappens struktur påverkar dess egenskaper. Arbetet utfördes med hjälp av en iterativ metod där koncept först togs fram och sedan utvärderades repetitivt tills ett slutgiltigt koncept var framtaget. Konceptframtagningen bestod av fem iterationer med faserna konceptgenerering, modellering, prototypframtagning, tester av prototyp och utvärdering. Arbetet resulterade i ett slutgiltigt koncept som ledde till en illustrerad prototyp i mindre skala som visar hur wellpappsprover skulle kunna skapas i SCA’s R&D-laboratorium. / Kraftliners are used to create, among other things, the surface layer for the paper product corrugated board. Corrugated board consists of a layer of kraftliner on either one or both sides of a wavy paper, called flute. On behalf of SCA R&D this bachelor's thesis investigates the possibility of creating a conceptual prototype for a machine that can create corrugated board samples in their laboratory. This is to be able to predict, via tests, how variations in the structure of the corrugated board affect its properties. The work was carried out using an iterative method where concepts were first developed and then evaluated repetitively until a final concept was developed. The concept development consisted of five iterations with the phases of concept generation, modeling, prototype development, prototype testing and evaluation. The work resulted in a final concept that led to an illustrated prototype on a smaller scale that shows how corrugated board samples could be created in SCA's R&D laboratory.