Characteristics of out-of-plane rheological behaviour of paper

Tero Ponkkala, Vesa Kunnari, Elias Retulainen

    Research output: Contribution to journalArticle in a proceedings journalScientific


    The dynamic strain behaviour of paper under z-directional compressive forces was investigated using a novel custom made testing rig. Laboratory hand sheets with same basis weights but different raw material composition were used. The plastic, elastic and creep components of strain caused by increasing stress and dwell time were determined and analysed. The results show that the logarithmic strain varied non-linearly with increasing stress level. The plastic deformation was causing the increase of the logarithmic strain. The increasing dwell time at constant stress caused also non-linear increase in strain. This was due to both increase in plastic component and decrease in elastic component. The results revealed also significant differences between mechanical and chemical pulp samples in both time and stress-dependent behaviour of strain probably due to the difference in the network structure. Large deformations occurred already in short time-scales.
    Original languageEnglish
    Pages (from-to)265-268
    Number of pages6
    JournalAnnual transactions of the Nordic Rheology Society
    Publication statusPublished - 2005
    MoE publication typeB3 Non-refereed article in conference proceedings
    Event14th Nordic Rheology Conference - Tampere, Finland
    Duration: 1 Jun 20053 Jun 2005


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