• Structural Engineering and Mechanics
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• 제7권1호
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• pp.53-67
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• 1999

The natural frequencies and modes of free vibration of specially orthotropic elliptic and circular plates are analysed using the Rayleigh-Ritz method. The assumed functions used are two-dimensional boundary characteristic orthogonal polynomials which are generated using the Gram-Schmidt orthogonalization procedure. The first five natural frequencies are reported here for various values of aspect ratio of the ellipse. Results are given for various boundary conditions at the edges i.e., the boundary may be any of clamped, simply-supported or fret. Numerical results are presented here for several orthotropic material properties. For rectilinear orthotropic circular plates, a few results are available in the existing literature, which are compared with the present results and are found to be in good agreement.

• 동력기계공학회지
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• 제5권4호
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• pp.38-43
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• 2001

This paper describes the effect of dynamic characteristics in tube line by external vibration conveying fluid with the power steering system. By the experimental analysis we found out that the factor of system vibration is the fluid-structure interaction of tube line. In fluid-filled tube system we study on the influence that the natural frequency of system and the frequency of wave motion produce upon through experiment. Experiments are modal test, frequency response function in continuous system, and vibrating tests when the system is driving with bolted clamping joint condition. From the results of the experimental studies, we obtained that the natural frequencies of system are very important than the wave induced vibrations. And we found that the tendency of system vibration level was decreased by bolting force, bolting condition and clamping distance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.164-168
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• 2004

The vibration analysis of an axially moving membrane are investigated when the membrane has the two sets of in-plane boundary conditions, which are free and fixed constraints in the lateral direction. Since the in-plane stiffness is much higher than the out-of-plane stiffness, it is assumed during deriving the equations of motion that the in-plane motion is in a steady state. Under this assumption. the equation of out-of\ulcornerplane motion is derived, which is a linear partial differential equation influenced by the in-plane stress distributions. After discretizing the equation by using the Galerkin method, the natural frequencies and mode shapes are computed. In particular, we put a focus on analyzing the effects of the in-plane boundary conditions on the natural frequencies and mode shapes of the moving membrane.

• 대한기계학회논문집A
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• 제28권3호
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• pp.274-280
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• 2004

This paper presents the analysis fur the radial vibration characteristics of cylindrical piezoelectric transducers. Taking into account the piezoelectric anisotropy, the differential equations of piezoelectric radial motion have been derived in terms of radial displacement and electric potential. Applying mechanical and electric boundary conditions has yielded a characteristic equation for radial vibration. Numerical analysis also has been carried out by using the finite element method. Theoretical calculations of the fundamental natural frequency have been compared with the experimental observations for transducers of several sizes. Comparison with the previous report of theoretical analysis simplifying the piezoelectric anisotropy into isotropy concludes that isotropic analysis is a reasonable process to predict the vibration characteristics of piezoelectric transducers.

• 한국정밀공학회지
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• 제17권7호
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• pp.203-208
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• 2000

The vibration of a mask degrades the color purity in CRT Therefore, a damping wire is put into contact with the mask to reduce the vibration in perfectly flat CRT. In this study, we analyzed the vibration of the mask contacting with the damping wire using FEM. First we calculated the natural frequencies and mode shapes of the mask by modal analysis, and compared them with the measured results to confirm our finite element model. The modal analysis of the wire was also performed to investigate resonance with the mask. Finally, the transient dynamic analysis of the mask contacting with the wire was performed. The vibration of the mask was measured to confirm our analysis, and the results are in good agreement with the analysis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.220-225
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• 2003

Recent issue of optical actuator is applying to mobile device. It leads actuator to become smaller than conventional type. This paper proposes the design of micro actuator plate spring and analysis of its vibration characteristic. Considering natural frequency of spindle motor, 1st and 2nd eigenfrequency of micro actuator must avoid its natural frequency. First, magnetic circuit is designed by using fine pattern coil and magnetic force is acquired by simulation program. Then, concept design is achieved by topology optimization. From concept design, micro actuator plate spring is embodied through DOE(design of experiment). Finally, considering vibration characteristic simultaneously, optimal plate spring design is determined by RSM(response surface method).

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.276-276
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• 2003

This paper dealt with an experimental study on the free vibration of circular-tube-beam submerged in water. A circular-tube-beam is commonly founded on the nuclear fuel assembly system in nuclear reactor. The nuclear fuel assembly susceptible to flow-induced vibration in nuclear reactor. So, the nuclear fuel assembly be designed to avoid any resonance due to the vibration during the reactor operation. In the experiment, applied boundary condition is clamped-free and the effect of water height to natural frequency and damping is studied. The experiment in air and in water has been performed. Used experimental method is impact exciting method. The natural frequencies and damping ratio according to water height is presented.

• 한국소음진동공학회논문집
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• 제12권3호
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• pp.221-227
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• 2002

The longitudinal and lateral in-plane vibrations of an axially moving membrane are investigated when the membrane has translating acceleration. By extended Hamilton's principle, the governing equations are derived. The equations of motion for the in-plane vibrations are linear and coupled. These equations are discretized by using the Galerkin approximation method after they are transformed into the variational equations, j.e., the weak forms so that the admissible functions can be used for the bases of the in-plane deflections. With the discretized equations for the in-plane vibrations, the natural frequencies and the time histories of the deflections are obtained.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.246-249
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• 2006

Finite element vibration analysis of the trial 5x5 partial fuel assembly in the still water was performed using the substructure method. ANSYS software was used as a finite element modeling and modal analysis tool. The calculated natural frequencies of the partial fuel assembly were more consistent with the experimental results for the identical test model compared to the much larger solid model. This modeling technique can be utilized for the fuel assembly dynamic behavior analysis under normal operation, seismic and loss-of-coolant-accident analysis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.176-180
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• 2006

When the vibration troubles occur on the ship structure during the sea trial, the rectification work is very restricted because of in-situ limitation. Usually, the finite element method is used to improve vibration characteristics of the structure, but it takes lots of time and effort in modeling the structure and adjusting the finite element model in order to consider appropriate boundary conditions of a complex ship structure. Therefore, experimental methods have been in general suggested to obtain proper countermeasures without time-consuming in modeling. In this paper, FRE(frequency response function) synthesis method is applied to estimate natural frequency of the modified ship structure, which is obtained from experimental and numerical methods.