The study of joints in Oak wood beam compared to the location of node and anti-node of longitudinal vibration

One of the problems of non-destructive tests in the detection of the inhomogeneities in wood and wood products is their location relative to the vibrating node and antinode. Thus, the hidden inhomogeneities located at the vibration node in such materials may not have any effects on the dynamic modulus of elasticity and may not be detectable. In this study, we investigated the development of simple end-to-end joint in oak beams (Quercus castaneifolia) with dimensions of 72×4×2 cm (longitudinal×Radial×Tangential), with blocks removed from the areas of 0.06 and 0.50 cm of the beam length. The blocks were removed from the same beam as the joint was developed. The results indicated that developing a joint in 0.50 cm of the beam length has no significant effect on values obtained from the dynamic modulus of elasticity while creating this joint in 0.06 cm of the beam length has a significant effect on values obtained from the dynamic modulus of elasticity. Also, in both joints, the damping and acoustic converting efficiency values were increased and decreased, respectively. The amount of these changes was more in the area of 0.06 cm of beam length. In general, it can be said that due to the effect of vibrating node and antinode and on the other hand, the location of the joint in both areas, the acoustic conversion efficiency factor is a suitable factor to estimate the location of the joint or the inhomogeneity itself.