Free Vibration Analysis of Thermally Buckled Composite LaminatePlates

• Main Authors: Chien-Chih Cheng, 鄭建智
• Other Authors: Le-Chung Shiau
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/99641483077415454522

碩士 === 國立成功大學 === 航空太空工程學系碩博士班 === 92 === 　　Base on the von karman large deflection plate theory, a 54 degree-of-freedom high precision higher order triangular plate element is developed for free vibration of thermally buckled composite laminated plate. For buckled plate, the total response of the plate is assumed to be the sum of displacement due to the buckled static deformation and that due to small dynamic deformation. The static deflection of the buckled plate is solved by using Newton Raphson iteration method. The natural frquency and free vibration mode of the plate can then be obtained in frequency domain after applying the static thermal postbuckling deflections into the equation of motion. Two different laminates are considered due to their distinct thermal expansion property. Results show that T300/5208 cross-ply laminate will be buckled earlier than the AS4/3501-6 laminate that makes the T300/5208 laminate stiffer and in term gives higher natural frequencies. The higher vibration mode of the cross-ply laminates will become the fundamental mode when the aspect ratio of plate goes higher. For the angle-ply laminates, a buckle pattern　change may occur in the post-buckling region and the natural frequencies of the laminates will also be changes abruptly. If the laminate is subjected to temperature gradient through the thickness, the plate becomes more stiffer and none of the natural frequencies will drop to zero as the temperature increases. Also, the vibration mode shift induced by buckle pattern change will occur slowly.