Estimation equations for moment resistances of L-type screw corner joints in case goods furniture

Abstract

The effects of the number of screws and screw sizes on bending moment resistance of L-type furniture corner joints constructed of particleboard (PB) and medium density fiberboard (MDF) with resin Surfacing were investigated ill this study. Six different sizes of screws which included two diameters (4 and 5 mm) and three lengths (40, 50, and 60 mm) were utilized for constructing the test specimens. Specimens were fastened with only screws. Two, three, and four screws were used in the joints of the specimens that have the same width. Specimens were tested under static compression loads that tended to close the joints and tension loads that tended to open the joints. Results indicated that the ultimate moment resistance was obtained with the MDF specimens when the number of screws was four in the joints. MDF corner joints yielded higher moment resistance than PB corner joints for both compression and tension tests. Test results also showed that a screwed corner joint became stronger as either screw diameter or screw length or number of screws was increased. Screw length was found to have a larger influence on bending moment resistance than screw diameter. Furthermore, the average bending moment resistances of screwed corner joints evaluated in this study in compression and tension could be estimated by means of the developed equations.