Free Vibration Analysis of Perforated Steel Plates with Various Cutout Curvatures and Rotations

J. Ocean Eng. Technol. 2010;24(6):61-70.

Woo Jin-Ho,Na Won-Bae

Department of Ocean Engineering Pukyong National University,Department of Ocean Engineering Pukyong National University

곡률과 회전을 고려한 유공 강판의 자유진동해석

우진호,나원배

부경대학교 해양공학과,부경대학교 해양공학과

Keywords: Free vibration analysis, Perforated steel plate, Curvature, Rotation, Finite element method, Natural frequency

핵심용어: 자유진동해석, 유공 강판, 곡률, 회전, 유한요소법, 고유진동수

Abstract

This study presents free vibration analyses of perforates steel plates with various cutouts. Four different parameters (shape, size, curvature radius ratio, and rotation of cutouts) were considered to investigate the effects of those parameters on the free vibration characteristics, such as natural frequencies of the perforated steel plates. Three different shapes of cutouts are circle, square, and triangle, and the considered sizes are 5, 10, 15, 20, and 25 mm. For the triangular and square cutouts, the characteristic radii of the inscribed circles of those cutouts were defined. In addition, the curvature radius ratio was defined as the ratio of curvature radius of bluntness and the characteristic radius. Then, total seven different curvature radius ratios (0, 0.1, 0.3, 0.5, 0.7, 0.9, and 1) were considered. To investigate the rotation effect of the cutouts, it was considered four rotations ($0^{circ}$, $15^{circ}$, $30^{circ}$, and $45^{circ}$) for the square cutouts and three rotations (0, 15, and 30) for the triangular cutouts. All the free vibration analyses were conducted using a general purpose finite element program. From the analyses we found that the most influential parameter for the free vibration response of the perforated plates is the size of cutout. The other factors such as the shape, curvature radius ratio, and rotation are minors; they mainly change the natural frequency as long as the size effect is accompanied.