EXPERIMENTAL VERIFICATION OF A NEW TOOL FOR WOOD MECHANICAL RESISTANCE MEASUREMENT

摘要

Many non-destructive methods for the assessment of wood incorporated in buildings are based on indirect measurement of density, which is closely related to the mechanical properties of wood determining the static condition of the construction. As thebest methods for the determination of density, various resistance methods have been proved, which react well to changes in the material structure in contrast to methods that are totally noninvasive (e.g. ultrasound methods). The paper presents a new diagnostic tool for "in-situ" assessment bf timber based on the principle of mechanical resistance of wood against tool (pin) penetration. To verify the proper function of the tool, measurements were conducted using three basic species of softwoods. With theaim to discern the variability of properties caused by their distribution along the diameter and the length of trunk, always one complete trunk of spruce, fir and pine was used. After cutting into sections, the selected trunks were subjected to analysisof physical and mechanical properties. The results show a very good correlation of the average force necessary for pin pushing penetration into the wood with wood density and compression strength parallel to the grain.