Author : Besnik Habipi and Dritan Ajdinaj

In this research, the effect of five different slope angels of the joint on bending strength of poplar (Populus alba L.) finger joint connection, bonded with polyvinyl adhesive, was studied. Modulus of rupture (MOR) and Modulus of elasticity (MOE) of joint perpendicular with strips edges, 15°, 20°, 25° and 30° slope joints, referring to the first one direction, were measured, according to norms ISO 3133 and 3349.120 samples in total, 24 samples for each type of joints, with dimensions 20x20x320 mm, were conditioned and tested by means of mechanical testing machine, in the Faculty of Forestry Sciences of Tirana. The MOR of perpendicular and 15° slope joints resulted almost the same, 36.75 N/mm2, while of 20° and 25° slope joints resulted 7% and 24% higher, respectively 39.16 and 45.66 N/mm2. With regard to the angel 30°, MOR value resulted 10% higher comparing to the straight connection, 40.33 N/mm2. Beyond the angel 25° modulus of rupture began to decrease. Modulus of elasticity wasn’t affected in a distinct manner by the slope angle of connection. For perpendicular joint it was 10152.12 N/mm2, while for 15°, 20°, 25° and 30° slope joints resulted 9944.91, 14484.8, 17697.59 and 10155.98 N/mm2 respectively. The research results obtained were discussed in order to analyze and evaluate the slope angle of finger jointing, which could affect its utilization potentials.

Keywords: finger joint, poplar, bending strength.

Article published in International Journal of Current  Engineering  and Technology, Vol.3,No.5(Dec- 2013)