Development and assessment of methods for determining wood and fibre orientation in a Douglas-fir timber specimen
摘要
Technologies utilising laser dot scanning to measure surface fibre orientation have evolved into advanced, system-ready solutions for machine strength grading. Although these methods significantly enhance predictive models of timber strength, they generally rely on surface-based interpolations that may not fully represent internal fibre architecture. In this study, a gradient structure tensor (GST) approach is investigated to estimate the normal direction of growth layers and infer internal fibre orientation. The method is compared with existing internal fibre orientation determination (IFOD) techniques combining laser dot measurements and destructive serial sectioning (DSS), and is assessed through local bending stiffness profiles derived from digital image correlation (DIC) tests and finite element (FE) simulations. Results indicate that accurate characterisation of internal fibre orientation, particularly when supported by laser dots-based measurements, enables highly reliable predictions of timber mechanical performance. DSS-based implementations yield determination coefficients of