A Finite Annular Plate Element with Slight Deviation for Vibration Analysis of a Nearly Axisymmetric Disk

Vibration of a nearly axisymmetric disk is analyzed by using a newly developed finite annular plate element with slight deviation from axisymmetry. Even if the developed annular plate element has four degrees of freedom, the annular element can contain the effects of slight deviation in density, stiffness or thickness. To provide validity of the proposed annular element, the natural frequencies of disks with deviation are computed by the finite element method using the new annular elements and the convergence and accuracy of the natural frequencies are investigated. It is shown that, when a disk has slight deviation, the finite element method using the proposed elements is more efficient to compute the natural frequencies and the mode shapes compared to a commercial code. Furthermore, the effects of deviation on the dynamic characteristics are also analyzed. Finally, it is evaluated how much deviation is acceptable for the proposed method to result in reliable computations.