Evaluation of resistance of wooden biscuit joints in mediumdensity fiberboard and particleboard under tensile and shear loads in T and L-type members

The aim of this study was to investigate the withdrawal resistance of T-shaped joints, shear strength and bending moment capacity in the diagonal tensile loading of L-shaped joints made of wooden biscuits.The type of joint members including medium density fiberboard (MDF) and particleboard and the size of biscuits 10 and 20 (one biscuit per joint) were the variables of this study. After constructing the specimens using polyvinyl acetate (PVAc) adhesive, the withdrawal resistance test of T-shaped joints and shear strength and bending moment capacity tests of L-shaped joints were carried out. The results of analysis of variance showed that the effects of independent variables namely, the composite type (Joint members) and the biscuit size on the the withdrawal resistance was significant in the 95% confidence level, also the effects of these independent variables on the shear strength and the bending moment capacity in diagonal tensile loading of the biscuit joints, was significant in the 95% confidence level. According to the results, T-shaped joints made of wood biscuits of MDF members have a higher withdrawal resistance than joints made of particleboard members. the withdrawal resistance of T-shaped joints made of Biscuit size of 20 was higher than that of joints made of Biscuit size of 10.The Shear strength and bending moment capacity in diagonal tensile loading of L-shaped joints made of MDF members were higher than those made of particleboard members. The L-shaped joints made of biscuit size of 20 showed higher shear strength and bending moment capacity in tensile loading, than joints made of biscuit size of 10. generally, the highest amount of tensile and shear strengths and bending moment capacity in tensile loading were observed in the joints made of MDF and biscuit size of 20.