Comparison of the strength properties of different joint techniques of frame construction furniture

In this study, on different joining techniques and wood spacies, longitudinal tension, diagonal compression, diagonal tension, the T-type bending and tensile strength properties of specimens of the frame-type joints were investigated. As wood material, beech (Fagus orientalis Lipsky), Scots pine (Pinus sylvestris Lipsky), oak (Quercus borealis Lipsky), chestnut (Castanea sativa) and walnut (Junglans regia) wood were used.At the experiments, first of all, some required physical and mechanical properties of wood materials used were determined. The physical properties of materials such as moisture content and density, and mechanical properties such as longitudinal tension, longitudinal compression, shear parallel to grain, tangential bending to grain and modulus of elasticity were determined in accordance with the relevant standards. In addition, the dowel holding strength and screw holding properties of the wood materials through parallel and perpendicular directions to the grain were also determined.Test specimens were prepared in three different forms as the I-type, L-type and T-type. As a joining type, mortise and tenon, dowel, screw, and minifix, maksifix joining were utilized. At glued joints (grooved, dowel), as adhesive, polyvinylacetate (PVAc) and polyurethane (PU) glue was used.As a result of the tests, at all joining elements and techniques, beech and walnut usuallly scored over other wood species. The lowest values were obtained from the chestnut and scots pine. The best results of joining techniques were obtained from motrise and tenon joints, while the lowest results were obtained from maxifix and minifix joints. At glued joints, polyvinylacetate glue rather than polyurethane glue and grooved joints rather than dowel yielded better results. At the dowel joint test specimens which were made by using Strain gauges, close results to the results calculated theorically are obtained, on the other hand, at the test specimens motrise and tenon joint applied, the results are not close, thus coefficients of error were identified.As a result of the study, as it is thought that tests done are the important stages of the furniture engineering, it is understood that the data obtained through the results of the experiments will help to see in advance the resistance weaknesses during usage and can give an idea about the damages it may have during usage. With the numerical data obtained through the research, testing the wood materials with different joint techniques and at various strenght elements and after that, doing performance tests on the 1 / 1 scale prototypes produced can be suggested for the further studies. Through this kind of scientific and systematic approaches, it can be claimed that the usage of the appropriate materials at appropriate areas will help the rise of the standarts thechnically and with the saving of comodity and labor economically will provide superiority to the concerning enterprices.