A numerical method for the evaluation of non-linear transient moisture flow in cellulosic materials

Research output: Contribution to journalArticle


A numerical method for the transient moisture flow in porous cellulosic materials like paper and wood is presented. The derivation of the model is based on mass conservation for a mixture containing a vapour phase and an adsorbed water phase embedded in a porous solid material. The principle of virtual moisture concentrations in conjunction with a consistent linearization procedure is used to produce the iterative finite element equations. A monolithic solution strategy is chosen in order to solve the coupled non-symmetric equation system. A model for the development of higher order sorption hysteresis is also developed. The model is capable of describing cyclic hardening as well as cyclic softening of the equilibrium water concentration. The model is verified by comparison with the measured response to natural variations in temperature and humidity. A close agreement of the simulated results to measured data is found. Copyright (c) 2005 John Wiley & Sons, Ltd.


  • Ulf Nyman
  • Per-Johan Gustafsson
  • Björn Johannesson
  • R Hagglund
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Materials Engineering
  • Mechanical Engineering


  • paper material, hysteresis, sorption, moisture transport, mixture model, multiphase model, virtual moisture concentration
Original languageEnglish
Pages (from-to)1859-1883
JournalInternational Journal for Numerical Methods in Engineering
Issue number12
Publication statusPublished - 2006
Publication categoryResearch