Role of finger tip area on flexural strength properties of finger-jointed sections

Abstract

This study reports the effect of two finger profiles on the static bending parameters of Eucalyptus tereticornis samples when joined with urea formaldehyde adhesive. Two sets of finger profiles with tip thicknesses of 0·11 and 0·14 cm were used. Interestingly, the profile with the thinner tip produced weaker joints. This behaviour is attributed to the larger contribution of the tip area to the total joint area in a joint when using the thinner tipped profile. The study suggests that for a given geometry, one needs to reduce the tip area in relation to the total area encountered in a joint. This gives the manufacturer an opportunity to make not too thin and fragile tips but still making it possible to design a profile which can result in useful strength parameters. The results obtained on the effect of tip area on bending parameters were confirmed by using another adhesive.

Keywords

Finger joint Finger geometry Tip thickness Urea formaldehyde PVA

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