Multi-stage parallel model in determining the quality of structural timber by the penetration method.

Multi-stage parallel model in determining the quality of structural timber by the penetration method. Various devices are used in situ to diagnose the quality of structural timber. A semi-destructive method is used for the approximate determination of wood density. The Pilodyn 6J uses a depth of cut that correlates with wood density. The experiments were performed on spruce wood (Picea excelsa, Karst. L.). Boards 40 x 200 x 2500 mm3, were tested, n = 5 pcs. The density of wood was determined by the gravimetric method according to EN 408 (2013). The penetration depth (hp), number and width of annual rings (RoG) were determined on the boards. Based on the density of the wood, the quality of the structural timber was specified by strength classes according to EN 338 (2016). The dependences between the measured characteristics were expressed in a model with a multi-stage parallel scale (penetration depth ~ number of annual rings ~ rate of growth ~ strength class and density wood). It is possible to predict visual strength class of board and indicative density of wood (EN 338) by the proposed model in situ. Methods of model are easy to use, reliable and economically undemanding. [ABSTRACT FROM AUTHOR]