Continuum material models of paper in folding simulations

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master_Koshelev_Mikhail_2025.pdf (29.6 MB)

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School of Engineering | Master's thesis
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Date

2025-07-08

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Building Technology

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Master's Programme in Building Technology

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en

Pages

74

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Abstract

The industrial production of paper and paperboard products often includes the process of folding. To optimize the production process and product performance, it is crucial to predict the mechanical behavior of the material accurately. The accuracy of the analysis depends a lot on the reliability of the structural and material models. The industrial folding process often includes a preparation phase, where a specific pretreatment is applied to a paperboard to improve its folding properties. This master's thesis attempts to compare different material models, from the very simple to more sophisticated ones, in their performance in folding simulations and the effect of various pretreatment techniques. This study considers three material models: the continuous isotropic piecewise linear model, the continuous orthotropic piecewise linear model, and the layered orthotropic piecewise linear model. For each model, two different pretreatment types are considered: the roller press, where a narrow roller is pressed along the folding line to compress the paper fibers in the thickness direction, and the half-cut, where a partial razor cut is made along the folding line. The results of the models with pretreatments are compared with those without pretreatment. The evaluation of these models is grounded in experimental three-point bending data and conducted through simulations using the ANSYS Workbench software package. This comparative analysis aims to assess the applicability and reliability of each material model under various pretreatment conditions. Three models were constructed with different levels of complexity. Simple models were able to reproduce the basic elastoplastic behavior during bending simulations. The layered orthotropic model was also able to capture the delamination phenomena.

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Supervisor

Niiranen, Jarkko

Thesis advisor

Niiranen, Jarkko

Keywords

paper, paper folding, material modeling, finite element method, ansys, delamination

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https://urn.fi/URN:NBN:fi:aalto-202508186278

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[dipl] Insinööritieteiden korkeakoulu / ENG