Modeling and Vibration Analysis of a Porous Rotational Shell Based on Biot Theory

Combining the Biot theory and classical elastic theory for thin shells, a new dynamic model of a thin fluid-saturated porous rotational shell is proposed. First-order ordinary differential control equations of the porous rotational shell are derived in the frequency domain. These equations are then solved by using the precise element method. The accuracy of this model has been verified by comparing with a vibration experiment. Moreover, the comparisons between the present model and two equivalent property models are carried out. Because the present approach considers the fluid-solid coupling effect and makes no assumptions for the fluid displacements, it is more accurate in the high-frequency range. Lastly, the dynamic characteristics of porous rotational shells are demonstrated by the proposed method.

A Semi-Analytical and Semi-Numerical Method for Acoustics Radiation Characteristics of Rotational Shells

A semi-analytical and semi-numerical method is presented for analyzing the acoustics radiation characteristics of a rotational shell. Combining the dynamics control equation and the sound pressure expression, the vibro-acoustics equation of the rotational shell is formulated firstly. Then, a semi-analytical method is developed based on the superposition principle. The comparisons with the document show that the proposed method is accurate and efficient.

Precision Element Method for Free Vibration Analysis of Rotational Shells with Partial Viscoelastic Core

Based on the elastic thin shell and layer wise theories, the first order differential matrix equation of a PCLD rotational shell is formulated. According to the principles of the finite element method and precision integration technology, a semi-analytical method, named precision element method, for the free vibration characteristic of a PCLD rotational shell is developed. Numerical results show that the present method is accurate and efficient.

A Structural Analytical Method of Underwater Observation Tower Due to Breaking Wave Forces

A structural design of the underwater observation tower constructed at wave breaking zone was studied in this research. Though the under water observation tower seems to be a rotational shell structure from its shape, actually, the rigid frame of beams and ribs exits inside wall, in which the frames are covered with curved plate element firmly against seawater pressure. Assuming that the observation tower was a pseudo-cylindrical shell, two results through our conducted research were applied for a practical structural analysis of the underwater observation tower. One is the unique and simple formula on added mass depending on elastic vibration, the other is transformation of total breaking wave forces into the wave pressure distribution over the surface of the observation tower. Using those results, the structural characteristic concerning displacement of the under water observation tower was examined through our own results.