Summary: | 碩士 === 國立交通大學 === 機械工程系 === 88 === In this thesis, vibration characteristics of the conical shell structures are studied, especially the characteristics of concentric modes with circumferential wave numbers equaling to one. For given edge loads, modal characteristics and responses in frequency range from 1k Hz to 10k Hz are determined for different shell structures. The changes of the modal frequencies and mode shapes are presented with different conical angles, profiles, boundary conditions, and material constants.
In analyzing thicker conical shells, shear along the thickness direction is considered based on the first-order shear deformation. The finite element analysis of the shell structures is achieved using the commercial code MSC NASTRAN. Experiments have been performed to verify the accuracy of the theoretical predictions. The effects of material properties on the behaviors of the shell structures have also been studied. It has been found composite conical shells have different behaviors from the isotropic ones. Both theoretical and experimental results on isotropic and composite conical shells are given for comparison.
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