多翼ファンの設計技術に関する研究 : 第1報,定常回転時に羽根に生じる応力の発生メカニズム

概要

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A multiblade fan is generally used as a sturdy and easy-to-use fan in many industrial fields. In conventional design, the structure of a fan blade is analyzed using Wiesmann's equation in which only bending deformation under centrifugal force is considered with the beam model. However, it is often reported that fatigue failures occur in fan blades designed using this equation. In this paper, the stress distributions on the blade were measured and the problem of Wiesmann's equation was clarified by comparison with experimental results. On the basis of experimental results, an original algorithm of deformation occurring in blades was proposed, and structural analysis of the fan blade was carried out by means of the finite element method (FEM) under the proposed algorithm. From these investigations, the results obtained are as follows. The body force due to centrifugal force generates torsional moment in addition to bending moment because positions of the center of gravity and the shear center don't coinside caused by the open section of the blade. This phenomenon causes stress concentration at both ends of the blade, and the stress caused by the torsional moment is dominant. It is suitable in design that the stress caused by trorsional moment be taken into consideration, as well as stress caused by bending moment, from the viewpoint of the fatigue strength.
一般社団法人日本機械学会の論文
1993-11-25