Rotation Stability of Anisotropic Disks

Abstract

The critical state caused by the loss of stability of coils in rotating anisotropic disks is investigated by a numerical method. The investigation is performed for different ratios between the circumferential and radial elastic moduli and different relative thicknesses of the disks, Poisson ratios, and the ratios of radial and shear moduli. It is shown that, if a disk is made of materials compliant in the radial direction, the coils can lose their stability and shift according to the first harmonic (with displacement of the center of mass of the disk) or the second and third harmonics of vibrations (without displacement of the center of mass) within the range of its rotational velocities. These vibrations can be real for some materials, e.g., for unidirectional composites with a compliant (polyurethane) binder, and can precede the failure of disks from the action of circumferential stresses.