The Study On Joint Property Of Oval-tenon Of Alnus Formosana Introduced By Sichuan

This paper have studied the influences include that of the tolerance parameters about the thickness and width of oval-tenon with the mortise on anti-pull strength, that of oval-tenon width on bending strength, that of oval-tenon position changes on breaking bending moment and rigid efficiency, that of different adhesives used in the experiment on anti-pull strength based on Alnus formosana introduced by Sichuan as material, and obtaining the follow results:(1) When the parameter (a) of the thickness of oval-tenon tolerance with the width of mortise is 0.3mm, the anti-pull forces achieve the maximum value namely 4.3359 KN. However, deformation of both tenon and mortise specimens occurs when assembled and anti-pull forces decreased significantly as (a) exceed 0.4mm. The expression of the connection about the ultimate pullout capacity(P) and the tolerance parameters(a) is: P=-3.2914α2+1.9737α+3.7908,(2)When the parameter (β) of the width of oval-tenon tolerance with the length of mortise is 0.6mm, the anti-pull forces achieve the maximum value namely 6.0453KN. When β exceed 1.0mm it is hard to match the tenon and mortise and deformation occurs on mortise specimens. The expression of the connection about the ultimate pullout capacity (P) and the tolerance parameters (β) is:P=-4.753102+5.9560β+4.3791.(3)The values of breaking bending moment increased with the increasing of oval-tenon width during 20mm-90mm. When the values of oval-tenon width varied from 60-90mm the breaking bending moment have a higher growth rate compared to that varied from 20-50mm.The expression of the connection about (M) and the oval-tenon width (C) is:M=0.0404C2+0.1113C+29.1532.(4) In the case of the distance (H) from tenon width direction to the one side of tip width direction take the same value,The anti-pull forces and breaking bending moment of T-junctions are greater than that of L-junctions when the (H) are equal. Inverse relationships between ultimate flexural forces and (H) and between the breaking bending moment and (H) were observed and the order of breaking bending moment is: T(H=0mm)>T(H=7.5mm)>L(H=7.5mm)>T(H=15mm)>L(H=15). T-junction’s rigid efficiency is greater than that of L-junction’s and it shows an inverse relationship between rigid efficiency and H. The order of the value of breaking bending moment is: T(H=0mm)>(H=7.5mm)>T(H=15mm)>L(H=7.5mm)>L(H=15mm).(5)The anti-pull forces is significantly influenced by the kind of adhesives that the value(6.1890KN) of specimen boned with industrial gelatin is higher than those bonded with other adhesives. The order is:industrial gelatin> two-component plate alignment adhesive> polyvinyl acetate>AB glue> multipurpose adhesive.