عنوان مقاله [English]
Rotating hollow cylinders are involved in many industrial applications. On the other hand, the advantages f unctionally graded materials have made them more attractive for application in different areas, such as in aircraft and aerospace industries. Because of this, in recent years, much research has been conducted on them. In this paper, maximum allowed angular velocity of a rotating hollow FGM cylinder is investigated. The analysis is based on he mall eformation theory. The cylinder is assumed to be infinitely long. Therefore, the deformation state in the cylinder is in a plane strain state. Youngs modulus, density and yield stress are assumed to be power-law functions of the radial oordinate. The maximum allowed angular velocity has been defined as the angular velocity at which yielding is initiated, based on the Tresca yield criterion. Dimensionless parameters have been introduced, based on the basic geometrical and material parameters of the problem. Then, the governing equation, which is an equilibrium equation in terms of radial displacement, has been solved analytically. The strain components have then been determined, using the obtained radial displacement and strain-displacement equations. Stress components are derived using the generalized Hooks Law. To identify stress component ordering, the radial distribution of dimensionless stress components was plotted. This was done for the special case of equal exponent parameters. The results show that for this special case, when the exponent parameters vary between -2 and 2, hoop stress and radial stress components are, respectively, the largest and the smallest stress components. Then, the effect of parameter variation, especially density and yield stress, on the maximum allowed angular velocity, is investigated. Results show that the radial variation of density and yield stress may have a considerable effect on stress distribution and yielding initiation, and, consequently, on the maximum allowed angular velocity. To the best of the authors knowledge, density variation was not taken into consideration in previously published research into this problem.