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Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/1270

Title: Effect of finger geometry and end pressure on the flexural properties of finger-jointed tropical African hardwoods
Authors: Ayarkwa, J.
Hirashima, Y.
Sasaki, Y.
Issue Date: 2000
Publisher: Forest Products Society
Citation: Forest Products Journal, vol. 50, No. 11/12
Abstract: Finger joints from three tropical African hardwoods, Obeche (Triplochiton sclemxylon), Makore (Tieghemella heckelil), and Moabi (Baillonella toxispenna), were prepared using three finger profiles, three end pressures, and resorcinol-formaldehyde adhe- sive, to assess the effect of the study variables on the flexural performance of the joints. Finger profile geometry was found to have a statistically significant influence on modulus of rupture (MOR), but not on modulus of elasticity (MOE) of finger joints from the three tropical African hardwoods. The finger profile F2 (18 mm (0.72 in.) finger length) exhibited the significantly strongest and the most efficient finger joiirts among the three finger profiles studied for each hardwood End pressure, however, was generally found to have no significant influence on MOR and MOE of the finger joints. Although the strongest finger joints seemed to have been produced when the profile F2 was combined with the end pressure of 12 N/mm2 (1,740 psi) for each species, end pressure of 12 N/mm2 resulted in lower joint efficiencies than 4 N/mm2 (580 psi) end pressure in Obeche and 8 N/mm2 (1,160 psi) in Moabi. From the viewpoint of economy, therefore, profile F2 combined with end pressures of4 N/mm2,12 N/mm2, and 8 N/mm2 seem the best combination of pro- duction variables for optimum finger joints in Obeche, Makore, and Moabi, respectively. Among the three hardwoods, finger-joints 'from the low-density Obeche exhibited the highest joint efficiency of 88 percent and wood failure of61 percent, followed by that from the medium-density Malooce of 78 and 29 percent, respectively. Finger joints from the high-density Moabi exhibited the lowest joint efficiency of 60 percent and wood failure of 14 percent. The results have shown that finger-joints of high flexural performance could be produced from the low-density Obeche and the medium-density Makore wood using the type of resorcinol-formaldehyde glue studied
Description: This article was published by Forest Products Society in 2000.
URI: http://hdl.handle.net/123456789/1270
Appears in Collections:College of Architecture and Planning

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