Yazar "Haviarova, Eva" seçeneğine göre listele

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    EVALUATING DESIGN OF MORTISE AND TENON FURNITURE JOINTS UNDER BENDING LOADS BY LOWER TOLERANCE LIMITS
    (SOC WOOD SCI TECHNOL, 2021) Uysal, Mesut; Haviarova, Eva
    This study aimed to estimate the design value for mortise and tenon joints. In this respect, the design value for static load tests was determined using lower tolerance limit methods. A lower tolerance limit value at 0.99/0.99 confidence/proportional level was chosen as a design value (199.05 N.m) to secure higher joint reliability in a furniture frame. A side frame of a simple wooden chair was theoretically analyzed to obtain internal forces acting on joints, whereas the load of 1000 N was applied in the vertical direction on the top of the front leg. A full-frame chair with mortise and tenon joints was then designed using the calculated lower tolerance limit design value. This action ensured that joints would not be overstressed when a chair is under static load while not exceeding 2000 N. By applying this method, all chairs should survive static load up to 2000 N. While performing cyclic front-to-back load test, all tested chairs met the American Library Association requirements for light-duty service load, specified for household chairs. This study demonstrates that a joint failure could be prevented under expected loads specified by the standard if the joint design value is known.
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    Use of lower tolerance limits for designing chair frames with round-end mortise and tenon joints
    (Taylor & Francis Ltd, 2025) Uysal, Mesut; Kuskun, Tolga; Smardzewski, Jerzy; Kasal, Ali; Haviarova, Eva
    In this study, the reliability of the mortise-tenon (MT) joints was examined experimentally and numerically. The joint strength has been determined empirically and numerically, but the reliability of the joint does not rely on a single asset - mean and standard deviation. The prediction of its strength also refers to a single value in the future population, but tolerance limits are related to a portion of the future population. Therefore, ensuring joint reliability comes into prominence not only for empirical data but also for theoretical and numerical analysis. For this purpose, the moment capacity of the T-shaped MT joints constructed of white oak was determined, and the lower tolerance limits (LTLs) approach was used to construct confidence/proportion (gamma/beta) levels for reliability. According to the results, the moment capacity of the MT joints was 341 Nm. The LTL values at 0.95/0.95, 0.99/0.95, 0.95/0.99, and 0.99/0.99 gamma/beta levels were 231, 226, 187 and 181 Nm, respectively. The normal stresses at each gamma/beta level were calculated based on the moment capacity and tenon sizes and were compared with the finite element method (FEM). Experimental and numerical results varied from 0.3% to 13.4%. Furthermore, a side frame was imposed to a vertical load of 1000 N on the front leg, and the moment of the joint on the side rail to the back post was measured (196 Nm). The side frame was modeled on ABAQUS - FEM software - and subjected to a moment of 196 Nm on the side rail. The theoretical and numerical results of stresses on joints differed from - 4.3% to 5.8%. The study showed that the reliability value is known, and; the joints could be designed by using FEM.