Strength and stiffness of reinforced l-shaped and t-shaped mortise and tenon joint

This paper investigated the strength and stiffness of L-shaped and T-shaped mortise and tenon joints with rounded shape of tenon. PVA-c glue was utilized to assemble the beech wood joints with interference fit. The strength was carried out by measuring maximal applied load and by calculating ultimate bending moment. Stiffness evaluation was conducted by measuring displacement and by calculating the ratio of applied force and displacement along the force line and the ratio of bending moment and rotation angle of the joint. The results were compared for common mortise and tenon joints and reinforced mortise and tenon joints. The joints were reinforced with round beech wood pegs i.e., standard dowels. The round peg passed perpendicular through the geometric center of the tenon cheeks. The results showed that, for the same tenon geometry but different shape of joints and test configurations, the maximum force of L-shape joints was higher than the force value of T-shape joints. However, the results showed small difference among the calculated bending moments of the analyzed type of tenon joints. The values of stiffness of L-shape joints and T-shape joints were notably different. A significant difference was not detected between the bending moment (strength) and stiffness of non-reinforced joints and reinforced joints for both L-shape and T shape joints. The investigation showed that the joints reinforced in this way could not be successfully used to improve mechanical properties of loaded mortise and tenon joints.