Investigating the stress carrying capacity of miter corner joints made with biscuit under diagonal tension and compression loading

This study was conducted to evaluate the stress carrying capacity of miter corner joints made with binder of biscuit under diagonal tension and compression loading. Corner joints with the Joint members from two species of beech (Fagus orientalis) and Fir (Abies alba), with 1 to 2 biscuits to size of 10 and 20 and with help adhesives of polyvinyl acetate (PVAc), polyurethane (PU) and urea formaldehyde (UF), they were made and tested. Since wooden pin joint is one of the most commonly included furniture joint, the test specimens were constructed using a pin and PVAc adhesive as a control for comparison with binder of biscuit. The results of analysis of variance showed that the independent effect of the species of Joint members, the size of biscuits, the number of binders and the type of adhesive in both compression and tensile loading is significant at 5% level. The results showed that the stress carrying capacity of the joints made with beech species is higher than that of fir species, and with increasing size and number of biscuits, the stress carrying capacity increases. The stress carrying capacity of the joints made with the polyurethane adhesive was also higher than those made joints with polyvinyl acetate and urea formaldehyde adhesives. The stress carrying capacity of the joints made under compression load was greater than the stress carrying capacity under the diagonal compression and tension load. The highest stress carrying capacity was observed in joints made with beech wood, two binders, biscuit size 20 and polyurethane glue, in both diagonal tension and compression loading.