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Analysis of the flexural vibration of ship's tail shaft by transfer matrix method

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Journal of Marine Science and Application 2008年第3期7卷 179-183页

作者：贾小俊范世东 School of Energy and Power Engineering Wuhan University of Technology

A ship's tail shaft has serious flexural vibration due to the cantilevered nature of the propeller's *** of the nature frequency of flexural vibration is vital to be able to provide effective shock absorption for a ship's tail shaft.A mathematic model of tail shaft flexural vibrations was built using the transfer matrix *** nature frequency of flexural vibration for an electrically propelled ship's tail shaft was then analyzed,and an effective method for calculating it was proposed:a genetic algorithm(GA),which calculates the nature frequency of vibration of a *** calculations,with comparisons by the Prohl method under conditions bearing isotropic support,showed this method to be *** should have significant impact on engineering design theory.

关键词： transfer matrix method flexural vibration nature frequency genetic algorithm

Principle of the retation of small particles around a nodal point of strip in flexural vibration

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Principle of the retation of small particles around a nodal ...

Drive of the micro particles at the nodal points of a copper substrate in flexural vibration mode

2011年全国压电和声波理论及器件应用研讨会

作者： Xiao-bo ZHU,Yu-jie ZHOU,Ning LI,Jun-hui HU~* State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China

＜正＞In this report,we investigate the principle of rotation of micro particles around a nodal point of metal strip in flexural vibration,by experimental measurement and theoretical *** is experimentally found that local travelling waves with the same travelling direction may exist along the circles centered at the nodal point of flexural vibration,

关键词： Local travelling wave Nodal point flexural vibration Particle Revolution

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Drive of the micro particles at the nodal points of a copper...

Study on rectangular ultrasonic radiator of flexural resonant vibration in high modes

2011年全国压电和声波理论及器件应用研讨会

作者： Hua-qing LI Jun-hui HU~* State Key Laboratory of Mechanics and Control of Mechanical Structures, Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China

＜正＞In this paper,the authors have put forward a novel method of using copper substrate to drive micro particles based on former research results about driving micro-particles on wedged vibration *** method firstly utilizes piezoelectric ceramics to excite copper substrate asymmetrically,and then makes use of local travelling waves

关键词： Micro particles Rotation Local traveling wave flexural vibration Copper substrate

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Chinese Journal of Acoustics 1993年第4期12卷 326-334页

Based on the theory of coupling vibration and flexural vibration of thin rod of rectangular cross section, the flexural vibration of rectangular thin plate was studied. The frequency equation was derived under the condition of free boundaries. The normal modes and the relation between the normal modes and the resonant frequency were obtained. Experiments showed that the calculated resonant frequencies agree well with the measured results, and the rectangular thin plate in flexural vibration has abundant resonant frequencies. The radiator of flexural vibration used in ultrasonic cleaning and other techniques has the advantages of large acoustic radiating area, uniform acoustic field and easy adjustment of resonant frequencies, proving that it is a promising ultrasonic source.

关键词： flexural vibration Resonant frequency Coupling vibration Ultrasonic radiator.

Stability and vibration of a helical rod with circular cross section in a viscous medium

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Chinese Physics B 2007年第4期16卷 891-896页

作者：刘延柱盛立伟 Department of Engineering Mechanics Shanghai Jiaotong University Shanghai 200030 China

The stability and vibration of a thin elastic helical rod with circular cross section in a viscous medium are discussed. The dynamical equations of the rod in the viscous medium are established in the Frenet coordinates of the centreline with the Euler angles describing the attitudes of the cross section as variables. We have proved that the Lyapunov and Euler conditions of stability of a helical rod in the space domain are the necessary conditions for the asymptotic stability of the rod in the time domain. The free frequencies and damping coefficients of torsional and flexural vibrations of the helical rod in the viscous medium are calculated.

关键词： thin elastic rod viscous medium torsional vibration flexural vibration

The vibroacoustic response and sound absorption performance of multilayer, microperforated rib-stiffened plates

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Acta Mechanica Sinica 2017年第5期33卷 926-941页

作者： Haian Zhou Xiaoming Wang Huayong Wu Jianbing Meng School of Mechanical Engineering Shandong University of Technology School of Mechanical Engineering Dalian University of Technology School of Aeronautics Shandong Jiaotong University

The vibroacoustic response and sound absorption performance of a structure composed of multilayer plates and one rigid back wall are theoretically analyzed. In this structure, all plates are two-dimensional, microperforated, and periodically rib-stiffened. To investigate such a structural system, semianalytical models of one-layer and multilayer plate structures considering the vibration effects are first developed. Then approaches of the space harmonic method and Fourier transforms are applied to a one-layer plate, and finally the cascade connection method is utilized for a multilayer plate structure. Based on fundamental acoustic formulas, the vibroacoustic responses of microperforated stiffened plates are expressed as functions of a series of harmonic amplitudes of plate displacement, which are then solved by employing the numerical truncation method. Applying the inverse Fourier transform, wave propagation, and linear addition properties, the equations of the sound pressures and absorption coefficients for the one-layer and multilayer stiffened plates in physical space are finally derived. Using numerical examples, the effects of the most important physical parameters-for example, the perforation ratio of the plate, sound incident angles, and periodical rib spacing-on sound absorption performance are examined. Numerical results indicate that the sound absorption performance of the studied structure is effectively enhanced by the flexural vibration of the plate in water. Finally, the proposed approaches are validated by comparing the results of stiffened plates of the present work with solutions from previous studies.

关键词： Sound absorption Multilayer Microperforated Rib-stiffened flexural vibration

Effects of ramp vibrational states on flexural intrinsic vibrations inBesocke-style scanners

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Chinese Physics B 2013年第6期22卷 591-595页

作者：张辉蒋国珠刘朝群张淑仪范理 Laboratory of Modern Acoustics Institute of AcousticsNanjing University

For both the vibrating and steady supporting surfaces of a scanning disk in a Besocke-style piezoelectric scanner, a theoretical model is given by considering the nonlinear lateral friction at the micro-contact interface between the positioning legs and the supporting surface. Numerical simulations demonstrate that unexpected flexural vibrations can arise from a vibrating ramp, and their frequencies are lower than the eigenfrequencies of the scanner in the linearly elastic regime. The vibrations essentially depend on 1） the vibrational states of the supporting ramp and the steel ball tips on the three piezo- electric positioning legs, and 2） the tribological characteristics of the contacts between the tips and the ramp. The results give an insight into the intrinsic vibrations of the scanners, and are applicable in designing and optimizing piezoelectric scanning systems.

关键词： Besocke-style scanner stick-slip behavior flexural vibration Timoshenko beam theory

Modal Control of Cantilever Beam Using a Gyrostabilizer

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Sound & vibration 2021年第4期55卷 281-294页

作者： OlkanÇuvalcı FarukÜnker Turgut Batuhan Baturalp Utku Gülbulak Atila Ertaş Department of Mechanical Engineering Karadeniz Technical UniversityTrabzon61080Turkey Department of Mechanical Engineering Gümüşhane UniversityGümüşhane29100Turkey Department of Mechanical Engineering Texas Tech UniversityLubbock79409USA

In this paper,an experimental model of a horizontal cantilever beam with a rotating/oscillating attached to the shaker for harmonic excitation at the one end and a gyrostabilizer at the other end is built to verify the equations of the Lagrangian *** primary focus of the study was to investigate the parameters of excitation amplitude,natural frequency,rotating mass(disk mass),and disk speed of gyro that would minimize the amplitude of the beam to identify these *** and experimental results indicate that the angular momentum of the gyrostabilizer is the most effective parameter in the reduction of beam displacement.

关键词： Cantilever beam rotating tip mass gyrostabilizer roll motion modal control flexural vibration

Removal of Dust on a Flat board using Focused Ultrasonic Waves

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Removal of Dust on a Flat board using Focused Ultrasonic Wav...