In this thesis, we studied and optimized demountable elastic snap-fit joints made of 9-ply 18 mm beech plywood. The aim of the research was to develop an engineeringly reliable joint for quick and repeated manual assembly and disassembly of outdoor furniture without the use of additional hardware or tools, suitable for digital CNC fabrication. In the first phase, we determined the orthotropic properties of the plywood through mechanical tests, which served as input data for computer simulations in the SolidWorks software. Using linear and non-linear simulations, we then parametrically analysed the effects of different lengths and thicknesses of the snap-fit cantilever on the compression and assembly forces of the joint. The theoretical results were evaluated by physical testing of CNC-manufactured specimens on a Zwick Z050 universal testing machine. The results prove that the stiffness of the joint is exponentially dependent on the thickness and length of the cantilever. With overly stiff cantilevers, mechanical jamming and plastic crushing of wood fibres occur, while excessively long cantilevers fail to provide adequate return force. Through proper dimensioning, the 6x90 mm and 9x150 mm geometries were determined to be the most optimal. For the highly recommended 6x90 mm geometry, the initial assembly force is 126 N, and after repeated use it drops by approximately 15% to 107 N. As a practical example of application, these findings were implemented in the conceptual design of a flat-pack demountable garden chair.
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