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P. Mackenzie-Helnwein, A. Hanhijärvi:
"Computational Analysis of Quality Reduction during Drying of Lumber due to Irrecoverable Deformation. II: Algorithmic Aspects and Practical Application";
Journal of Engineering Mechanics (ASCE), 129 (2003), 9; 1006 - 1016.

This paper describes the development of an efficient numerical integration algorithm for an orthotropic viscoelastic-mechanosorptive-plastic material model for wood, which has been presented in Part~I of this serial. This development utilizes both a semi-analytical algorithm for the viscoelastic parts, and the return-mapping algorithm known from plasticity for the mechanosorptive-plastic part of the model. This yields an easy to be computed, closed form expression for the consistent tangent operator, and, as a consequence, a quadratic rate of asymptotic convergence on the global level of the incremental-iterative analysis by means of the FEM.

To prove the practical applicability of the presented formulation, a numerical study of the so-called casehardening phenomenon as observed on fast dried pine wood has been performed and selected results are presented. For a representative variation of process parameters, the simulation reproduces well the experimentally observed tendency. The developed numerical formulation proved effective and stable with respect to large time steps and thus presents a powerful tool for the simulation of drying stresses and shape distortion during subsequent manufacturing.

Keywords: plasticity, creep, wood, mechano-sorption, drying, numerics

http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC04403084

http://dx.doi.org/10.1061/(ASCE)0733-9399(2003)129:9(1006)