Modeling morphological features of timber from X-ray tomographic images

The use of timber, as engineering material, is influenced by the wood heterogeneous structure, which can be observed hierarchically over a spectrum of length scales. At the macroscopic level, mechanical properties of wood are affected by anatomic characteristics such as annual ring thickness, knots, checks, etc. In some applications, in order to depict the variability of mechanical properties, numerical modeling of wood should account for material heterogeneity. In this case, a possible approach is to have the model closely match the structure of the real specimen, by implementing so called “morphology-based models”. In this case, for the definition of a realistic geometrical domain of the numerical model, a description of the investigated structures is necessary. For this purpose, non-destructive imaging techniques, such as X-ray tomography, can be used. In this paper, we describe a method by which the morphological features of the timber material, at the macro scale, can be modeled from computed tomography images. Conversion of three-dimensional image data into geometrical models, by using state-of-the-art image-based techniques, available through use of commercial software is briefly discussed. A novel methodology is also presented. The implemented method allows overcoming the major drawback of traditional approaches used for the generation of models from computer-assisted design data, which is the lack of automation in the model construction pipeline. Advantages and limitations of the different methodologies are discussed.