energies
Article Crushing of Single-Walled Corrugated Board during Converting: Experimental and Numerical Study
Tomasz Garbowski 1 , Tomasz Gajewski 2, * , Damian Mr ó wczyn´ski 3 and Radosław Je˛drzejczak 4
1 Department of Biosystems Engineering, Poznan University of Life Sciences, Wojska Polskiego 50, 60-627 Poznan´ , Poland; tomasz.garbowski@up.poznan.pl 2 Institute of Structural Analysis, Poznan University of Technology, Piotrowo 5, 60-965 Poznan´ , Poland 3 R&D Department, FEMat Sp. z o.o., Romana Maya 1, 61-371 Poznan´, Poland; damian.mrowczynski@fematproject.pl 4 Werner Kenkel Sp. z o.o., M ó rkowska 3, 64-117 Krzycko Wielkie, Poland; radoslaw.jedrzejczak@wernerkenkel.com.pl * Correspondence: tomasz.gajewski@put.poznan.pl Abstract: Corrugated cardboard is an ecological material, mainly because, in addition to virgin cellulose fibers also the fibers recovered during recycling process are used in its production. However, the use of recycled fibers causes slight deterioration of the mechanical properties of the corrugated board. In addition, converting processes such as printing, die-cutting, lamination, etc. cause micro- damage in the corrugated cardboard layers. In this work, the focus is precisely on the crushing of corrugated cardboard. A series of laboratory experiments were conducted, in which the different types of single-walled corrugated cardboards were pressed in a fully controlled manner to check the impact of the crush on the basic material parameters. The amount of crushing (with a precision of 10 micrometers) was controlled by a precise FEMat device, for crushing the corrugated board in the range from 10 to 70% of its original thickness. In this study, the influence of crushing on bending, twisting and shear stiffness as well as a residual thickness and edge crush resistance of corrugated board was investigated. Then, a procedure based on a numerical homogenization, taking into account a partial delamination in the corrugated layers to determine the degraded material stiffness was proposed. Finally, using the empirical-numerical method, a simplified calculation model of corrugated cardboard was derived, which satisfactorily reflects the experimental results.
Citation: Garbowski, T.; Gajewski, T.; Mrówczyn´ ski, D.; Je˛drzejczak, R. Crushing of Single-Walled Corrugated Board during Converting: Experimental and Numerical Study. Energies 2021 , 14 , 3203. https:// doi.org/10.3390/en14113203
Keywords: corrugated cardboard; converting; numerical homogenization; strain energy equivalence; finite element method; shell structures; transverse shear
Academic Editor: Peter Foot
Received: 6 May 2021 Accepted: 27 May 2021 Published: 30 May 2021
1. Introduction Paper and cardboard are made of cellulose fibers that mainly come from trees. Some of the fibers circulate repeatedly in the production-recycling loop. The material is, therefore, environmentally friendly, but the quality of the produced material from recycled fibers iteratively declines. This requires a deeper understanding if one wants to optimize the product and at the same time keep the material eco-friendly. It becomes even more important if the final product is a corrugated cardboard, which consists of two to seven alternating flat (liners) and corrugated (fluting) layers of paperboard. The particular orientation of the fibers resulting from the cardboard production process causes the material to have different mechanical properties along the mutually perpendicu- lar directions. Such materials are called orthotropic materials, as opposed to isotropic ones, which exhibit the same physical properties independent of the direction. The material ori- entation along the fibers that follow the direction of the web during production is called the machine direction (MD), the direction perpendicular to it is called the cross direction (CD). As the material is much stiffer and stronger in MD (along fibers), the corrugated board production method compensates for its poorer behavior in CD by using the corrugated
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Energies 2021 , 14 , 3203. https://doi.org/10.3390/en14113203
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