MODELING THE EARLYWOOD AND LATEWOOD GROWTH RINGS OF NORWAY SPRUCE TIMBER BEAMS FOR FINITE ELEMENT CALCULATION

Abstract

The purpose of this research is to determine the orthotropic material properties oftheNorway spruce (Picea abies) and to develop a finite element modeling technique that, when applied to an individual specimen, can properly predict the outcome of the measurement results (i.e., deflection by a predefined loading) by simulation only. For the development ofthefinite element model of timber beams, their unique annual ring pattern is considered. TheHSV color spectrum of picture of the end grain pattern is analyzed with a photo analytical algorithm in order to separate the phases, earlywood and latewood. The determined surface ratio of thephases is used to hypothesize that the volume and surface ratios are equal. For thedescription of wood as a material the rule of mixtures is used. The results of thecompared measurements and FE models based on the introduced hypotheses show good agreement within the linear elastic limit.