Modelling of growth inhomogeneities in timber structures for realistic computations

This contribution discusses the numerical analysis of timber structures by means of the Finite Elements Method. As a naturally grown and fibrous material, wood shows distinctive material directions, which are captured by a cylindrically anisotropic model. Due to the growth conditions of a tree, the fiber course in wooden structural parts can differ. Especially branches, leading to knots, affect the mechanical properties. Therefore, an approach for the modelling of these growth inhomogeneities is presented. For the three-dimensional determination of the fiber course in the area of the inhomogeneities, an optimization procedure, using the idea of minimization of shear stresses in tree growth, has been developed. (© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)