A novel method and validation for obtaining the optimal interference fit of round-end mortise-and-tenon joint

Abstract

ABSTRACT To determine the optimal interference fit of mortise-and-tenon (M&T) a novel method is proposed. To validate its effectiveness, compression tests were conducted considering the effects of wood species (beech and western hemlock), tenon widths (30, 40, 50 mm), and grain orientations (radial, diagonal, and tangential) to obtain the optimal interference fit and contact force (CF). Furthermore, the mounting force (MF) and withdrawal force capacity (WFC) of T-shaped M&T joints constructed by the control and optimal interference fit were evaluated by compression and withdrawal tests, respectively. The results indicated that (1) all three evaluated factors had significant effects on the tenon compression behavior and CF; (2) the derived optimal fits showed that the tenon with a larger width required a higher fit value based on regression equations; (3) the MF and WFC were significantly affected by the three evaluated factors and proportional to the tenon fit; (4) the maximum WFC occurred at the M&T joints made of western hemlock with 50-mm tenon width in tangential orientation with 0.99-mm interference fit, and the beech with 30-mm tenon width in diagonal orientation with 0.78-mm interference fit. The proposed method will assist the wood product manufacturers to design M&T joints rationally.