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E. Bosco, R. Peerlings and M. Geers. A micro-mechanical modelling study of drying restraint effects on the hygro-mechanics of paper sheets. In Advances in Pulp and Paper Research, Oxford 2017, Trans. of the XVIth Fund. Res. Symp. Oxford, 2017, (W.Batchelor and D. Söderberg, eds), pp 627–649, FRC, Manchester, 2018.


In this contribution we show how fibre activation and micro-buckling of fibre walls may explain, quantitatively, differences in the hydro-mechanical response of paper sheets due to the presence or absence of mechanical restraint during their fabrication. To this end, both effects are incorporated in an idealised micro-mechanical model of the fibre network. The model is used to predict the response of the network to wetting-drying cycles, as a function of the degree of restraint during production. Restrained-dried networks are predicted to exhibit an irreversible hygroscopic strain upon first wetting and a different reversible hygro-expansivity coefficient, compared with free-dried networks, which match well with experimental values reported in the literature.

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