Thermo-Mechanical Limit Angular Speed Analysis of Trigonometric Functionally Graded Disks

Abstract

Limit elastic speed analysis describes the operating range of speed for rotating structures that are widely utilised in industries. Because of centrifugal loading, stresses induced in the disk increase with speed until reaching a point when the induced stress reaches the yield strength. The disk location where it coincides is known as the yield location and the matching speed is the limit angular speed of the disk. Metal-ceramic functional grading can enhance toughness at elevated temperatures. Trigonometric functional grading was chosen to maximise the yield strength at the inner radius and outer radius of the disk. The approach utilised is the variational principle, deriving the solution through Galerkin's error minimisation method. Validation of the findings was performed using finite element analysis with ANSYS software, which shows satisfactory alignment. Analysis of various aspect ratios indicated a reduction in limit speed as the aspect ratio increased. The position of yielding was identified at the root for a uniform thickness disk and varying disk profiles. With the present functional grading, a significant improvement in disk performance is expected.