Analysis of the Static Equilibrium Equation of the Oval Mortise and Tenon Joint According to V.N. Mihajlov and V.D. Bekhtejarov

The study analyzes the deviations of the strength values ​​of the oval tenon-mortise joint obtained experimentally in relation to the values ​​obtained by calculating the torsional moment M3, based on the Mihajlov and Bekhtejarov formulas presented by Tkalec and Prekrat (2000). The strength was analyzed by measuring applied load and by calculating ultimate bending moment. In the paper, only the ratio of the tenon side dimensions l:b was varied (l-tenon length; b–tenon height). By analyzing the experimental results, it can be seen that the bending strength and stiffness of the joint increase as the tenon dimensions increase. The results have shown that joint stiffness depends first of all on the tenon width, and the effects of the tenon length are less significant. In the case when the tenon width is greater than its length the Saint–Venant coefficient cannot be applied in the form in which it is given in the analyzed literature. By applying the Saint–Venant coefficient in that form, the calculation results significantly deviate from the results obtained experimentally. The torsional moment equation should be used in its modified form only when the usual dimensions of tenon and mortise are applied.