Improvement of the bending moment capacity of mitered MDF frame under diagonal tension by using of the densified poplar dowel

The aim of this study was to improve the joints of the mitered furniture frames by using the densified poplar dowels (Populus alba) instead of beech dowels. Therefore, the effects of the dowel number (one and two dowels), dowel diameter (8, 10, and 12mm), and compression ratio (0, 15, and 30%) on bending moment capacity of L-shaped frame corner joints constructed of medium-density fiberboard (MDF) under diagonal tension load were investigated. Then, their performance was compared with those manufactured with beech dowels. Polyvinyl chloride (PVA) was used for gluing the joints. Diagonal loading was performed by Hounsfield (model No. 0380) testing machine with a 5 mm/min loading rate. The results revealed that the bending moment capacity of joints was increased 105.5, 54.3, and 28.75% respectively with the increase of the dowel number, dowel diameter, and compression ratio. The highest bending moment capacity was observed in the joints made out of two 30% compressed dowels with a diameter of 10 mm, and the least of them were seen in joints constructed of one uncompressed dowel with a diameter of 8 mm. the comparison of the joints dowelled by poplar with beech showed that the difference among the bending moment capacity of joints made of poplar dowels with 30% compression ratio and beech dowels was very small (less than one percent), which indicates usability of the densified poplar dowels instead of beech ones.