Micro-mechanical modeling of irreversible hygroscopic strain in paper sheets exposed to moisture cycles

INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES

卷:224

Article

Samantray, P.^1,2,3  Peerlings, R. H. J.¹  Massart, T. J.²  Geers, M. G. D.¹ 

[1] Eindhoven Univ Technol, Dept Mech Engn, POB 513, Eindhoven, Netherlands

[2] Univ Libre Bruxelles, Bldg Architecture & Town Planning, 50 Ave FD, B-1050 Brussels, Belgium

[3] Mat Innovat Inst M2i, POB 5008, NL-2600 GA Delft, Netherlands

关键词: Fibrous network;    Hygro-mechanics;    Micro-mechanics;    Homogenisation;   

DOI  :  10.1016/j.ijsolstr.2021.03.011

来源: Elsevier

【 摘 要 】

Paper is a complex material consisting of a network of cellulose fibres at the micro-level. During manufacturing, the network is dried under restraint conditions due to tension in the paper web in machine direction. This gives rise to internal strains that are stored in the produced sheet. Upon exposure to a moisture cycle, these strains may be released. This results in permanent shrinkage that may cause instabilities such as curl or waviness of the sheet. The prime objective of this paper is to model this irreversible shrinkage and to link its magnitude to the properties of the fibres and of the network. For this purpose, randomly generated fibrous networks of different coverages (i.e. ratio of the area occupied by fibres and that of the sheet) are modeled by means of a periodic representative volume element (RVE). Within such RVEs, a finite element method combined with a kinematic hardening plasticity model at the scale of the fibres is used to capture the irreversible response. The computational results obtained demonstrate that the magnitude of the irreversible strains increases with coverage until a certain coverage and beyond that coverage decreases in magnitude. This phenomenon is explained by considering the area fraction of freestanding fibre segments relative to bonded fibre segments in the network. A structure-property dependency of irreversible strains at the sheet-level on the micro-structural parameters of the network is thereby established. (C) 2021 The Authors. Published by Elsevier Ltd.

【 授权许可】

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