鐘形셀의 두께變化 및 非對稱效果에 따른 振動모우드 解析에 관한 硏究 = Modal Analysis of the Bell Type Shell with Thickness and Asymmetric Effects

국문 초록 (Abstract)

본 논문에서는 이들 기본모우드형태가 검토되었고 또한 두께효과와 비대칭성 효과에 따른 고유진동주파수, 모우드형태, 울림주파수의 변화를 수치적 해석과 실험 적 해석방법에 의해 비교검토되었다. 수치해석방법은 유한요소법으로 이용된 프로그 램은 NASTRAN 프로그램이고 모우드의 형태는 Tectronics컴퓨터그래픽을 이용하여 나타 내었다. 실험적방법은 충격햄머법과 F.F.T. 분석장치(Fast Fourier Transformation Analyzer)를 이용하였다.

다국어 초록 (Multilingual Abstract)

Mode shapes and natural frequencies of the bell type shell are analyzed numerically by the finite element method. The impulse hammer method and the Fast Fourier Transform analyzer are used for the experimental test. All types of mode shapes are expressed by the computer graphics. Numerical solutions are good agreement with the experimental results. The sustaining sound of the typical bell-type shell depend upon the first flexural mode (0-2 mode) and the second flexural mode (0-3 mode), and their mode shapes are independent upon thickness Dangjwas, holes, and added mass effects. Asymmetric effects by Dangjwas, holes and added mass give rise to beat frequencies, and the added mass is found to be most effective.