P. Helnwein, A. Hanhijärvi, J. Eberhardsteiner:
"Long-Term Behavior of Wood Under Multiaxial States of Stress and Simulation of Structural Details";
in: "CD-ROM Proceedings of the World Conference on Timber Engineering", University of British Columbia, Whistler Resort, British Columbia, Canada, 2000.
The aim of the present paper is to study the effect of moisture content changes on the deformation behavior of structural details subjected to static load. These studies are performed by means of a 3-dimensional extension of an existing nonlinear 1D-model for mechano-sorptive creep and its application within the Finite Element Method (FEM).
Within this paper, a brief overview of the theoretical formulation of the orthotropic creep model and the related description of moisture transport are given. The basic steps of the generalization of the 1D-model for arbitrary 3-dimensional states of stress on the basis of a generalized Maxwell model are shown and a fully 3-dimensional formulation is presented. Prove of applicability of the model is given by means of two representative 3-dimensional examples, analyzed using the nonlinear FEM. These examples cover bending of beams and the analysis of the long-term deformation behavior of a joint both under cyclically varying humidity.