Experimental study of the stress state in a welded conical drum with internal stiffeners using an elastic tensometric model

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1. Experimental checking of the engineering method of calculation for a welded conical drum confirms that it should be used to determine the main structural dimensions in the initial stages of development. The proposed calculation scheme can be used to find with a fair degree of speed and accuracy the most unfavorable combination of external force factors acting on the drum. 2. The calculation scheme for the conical power drum with internal stiffeners makes it possible to find the stresses in the drum by using the theory of thin-walled bar-shells with an open cross-sectional profile developed by V. Z. Vlasov and A. A. Umanskii. This scheme may be recommended as a more precise engineering method of calculation to determine the main structural dimensions of the drum for strength and rigidity. 3. The arrangement of forces in the experimental installation permits more accurate simulation of the effect of all possible combinations of concentrated forces and moments acting on a power drum fixed at one end on the side of the larger cone diameter. 4. The experimental results confirm the basic propositions in the improved method on the necessity for taking account of stresses arising from the action on the drum of external force factors in and out of the plane of its curvature. The effect of the force factors is taken up by the whole meridian section of the drum, not solely by the middle stiffener to which external load is applied. The normal stresses at the points of fixing of the fairing are much lower than the permissible stresses, which confirms the theoretical conclusion on the necessity for taking account of the elastic fixing of these sections against warping, using the experimental method. The most unfavorable case is that in which external load is applied to two adjacent bushes when the moments are in one direction. 5. The proposal that fillets should be included in the structure of a power drum at the points where the bushes are welded on has been substantiated and recommended. The results of the experimental and theoretical studies make it possible to substantiate the structural strength of a control mechanism power drum.