Modeling the earlywood and latewood growth rings of Norway spruce timber beams for finite element calculation
The purpose of this research is to determine the orthotropic material properties of the Norway 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 of the finite element model of timber beams, their unique annual ring pattern is considered. The HSV 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 the phases is used to hypothesize that the volume and surface ratios are equal. For the description of wood as a material the rule of mixtures is used. The results of the compared measurements and FE models based on the introduced hypotheses show good agreement within the linear elastic limit.