• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.6
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• pp.96-102
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• 2000

Spinning mechanism is generally used in coasting process on grass plates. Rebounding PR(Photo Resist) which leads to occur inferiority of coating process is caused by vibrational energy of whole coating system. In this study, the sensitivity analysis is performed to analyze and reduce vibrational terms in the spin coating system. The sensitivity analysis is bared on the numerical expression of this system. By the bond graph method. power flow of each system is represented by some basic bond graph elements. Any energy domain system is modeled using the unified elements. The modelled spin coater system is verified with power spectrum data measured by FFT analyzer. As the results of verifying model parameters and sensitivity analysis, principal factors causing vibration phenomenon are mentioned. A study on vibration method in the spin coating system is discussed.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.170-175
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• 2005

In this study, experimental and theoretical methods were applied to understand brake squeal noise VVVF rolling stock on tracks. Trailer cars needed to payed a particular attention, because they were the major source of brake noise. VVVF rolling stocks for lines no 1 of the subway system in Seoul were used for experimental analyses. In order to study brake squeal noise, a dynamometer test at the S&T Brake, Co., which was a manufacturer of brake pads had performed. For measuring vibration and noise, vibration tests of brake parts (brake lining, brake lining head, back plates, etc.) at the SNUT were executed. Also, vibration tests of disc assembly and lining block at the heavy maintenance shop of the Gunja depot were performed. The modal analyses by using an ANSYS which was one of the CAE commercial program were simulated to know the relationship to the mechanism of brake noise. On the based of the tests and the simulations it was found that specific frequencies of the brake parts affected squeal noise, and improvements for reducing squeal noise were proposed.

• International Journal of Naval Architecture and Ocean Engineering
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• v.7 no.2
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• pp.324-345
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• 2015

A new procedure for determining properties of thick plate finite elements, based on the modified Mindlin theory for moderately thick plate, is presented. Bending deflection is used as a potential function for the definition of total (bending and shear) deflection and angles of cross-section rotations. As a result of the introduced interdependence among displacements, the shear locking problem, present and solved in known finite element formulations, is avoided. Natural vibration analysis of rectangular plate, utilizing the proposed four-node quadrilateral finite element, shows higher accuracy than the sophisticated finite elements incorporated in some commercial software. In addition, the relation between thick and thin finite element properties is established, and compared with those in relevant literature.

• Journal of the Korean Society for Precision Engineering
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• v.15 no.9
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• pp.68-74
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• 1998

The ESPI(Electronic Speckle Pattern Interferometry) is a real time, full-field, non-destructive optical measurement technique that allows static and dynamic deformation analysis and surface shape measurements of engineering structures. e .g. turbine blades. vehicle engine components, body panels, etc. This technique is very similar to holographic interferometry, but uses a solid static camera and an image processing board for recording and digital processing of speckle patterns. In this paper it is presented that FEM results for the free vibration of symmetrically laminated composite as [30/-30/90]s. The natural frequencies of laminated composite rectangular plates having the particular boundary condition are experimentally obtained. In order to demonstrate the validity of the experiment, FEM analysis using ANSYS was performed and natural frequencies experimentally obtained is compared with calculation by FEM analysis. The results obtained from both experiment and FEM analysis show a good agreement.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.715-718
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• 2005

For accurate prediction of the thermal shock-induced vibrations, this paper develops a spectral element model for usually moving thermoelastic beam-plates. The spectral element model is formulated from the frequency-dependent dynamic shape functions which satisfy the governing equations in the frequency-domain. Some numerical studies are conducted to evaluate the present spectral element model and also to investigate the vibration characteristics of an example axially moving beam-plate subjected to thermal loadings.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.240-243
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• 2005

A design procedure using spatial Fourier transform is presented for a structural-acoustic coupled radiator that can emit sound in the desired direction with high power and low side lobe level. The design procedure consists of three steps. Firstly, the structural-acoustic coupled radiator is chosen to obtain strong coupling between structural vibration and acoustic pressure. The radiator is composed by two spaces which are separated by a wall. Spaces can be categorized as reverberant finite space and unbounded semi-infinite space, and the wall are composed of two plates and an opening. The velocities on the wall are predicted. Secondly, directivity and energy distribution of radiator are predicted in wave number domain using spatial Fourier transform. Finally, optimal design variables are calculated using a dual optimal algorithm. Its computational example is presented including the directivity and resulting pressure distribution using proposed procedure.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.916-921
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• 2001

형상기억합금 선(Shape Memory Alloy Fibers ： SMA Fibers)을 삽입한 복합재료 평판의 고온 환경에서의 열적 좌굴 및 진동 해석을 유한요소법을 이용하여 수행하였다 1 차 전단변형이론을 적용하여 적층판을 모델링하였고, 온도 변화 효과는 적층판의 전 영역에서 균일한 온도 분포로 가정하였다. 형상기억합금 선의 온도에 대한 비선형 재료 성질을 고려하여 열적 좌굴 해석 수행 시 반복 계산법을 이용하였고, 자유 진동 해석에서는 시스템의 자유도를 줄이기 위하여 Guyan-Reduction(CR)을 사용하였다. 온도 변화와 형상기억합금 선의 체적비(volume fraction) 및 초기 변형률(initial strain) 변화에 따른 임계 온도와 고유 진동수의 특성을 해석하였다.

• Advances in nano research
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• v.5 no.4
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• pp.393-414
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• 2017

Forced vibration behavior of porous metal foam nanoplates on elastic medium is studied via a 4-variable plate theory. Different porosity distributions called uniform, symmetric and asymmetric are considered. Nonlocal strain gradient theory (NSGT) containing two scale parameters is employed for size-dependent modeling of porous nanoplates. The present plate theory satisfies the shear deformation effect and it has lower field variables compared with first order plate theory. Hamilton's principle is employed to derive the governing equations. Obtained results from Galerkin's method are verified with those provided in the literature. The effects of nonlocal parameter, strain gradient, foundation parameters, dynamic loading, porosity distributions and porosity coefficient on dynamic deflection and resonance frequencies of metal foam nanoscale plates are examined.

• Structural Engineering and Mechanics
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• v.71 no.3
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• pp.257-269
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• 2019

This paper develops a nonlocal strain gradient plate model for damping vibration analysis of smart magneto-electro-viscoelastic nanoplates resting on visco-Pasternak medium. For more accurate analysis of nanoplate, the proposed theory contains two scale parameters related to the nonlocal and strain gradient effects. Viscoelastic effect which is neglected in all previous papers on magneto-electro-viscoelastic nanoplates is considered based on Kelvin-Voigt model. Governing equations of a nonlocal strain gradient smart nanoplate on viscoelastic substrate are derived via Hamilton's principle. Galerkin's method is implemented to solve the governing equations. Effects of different factors such as viscoelasticity, nonlocal parameter, length scale parameter, applied voltage and magnetic potential on damping vibration characteristics of a nanoplate are studied.

• Coupled systems mechanics
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• v.8 no.3
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• pp.247-257
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• 2019

Fee vibrational characteristics of porous steel double-coupled nanoplate system in thermo-elastic medium is studied via a refined plate model. Different pore dispersions called uniform, symmetric and asymmetric have been defined. Nonlocal strain gradient theory (NSGT) containing two scale parameters has been adopted to stablish size-dependent modeling of the system. Hamilton's principle has been adopted to stablish the governing equations. Obtained results from Galerkin's method are verified with those provided in the literature. The effects of nonlocal parameter, strain gradient, foundation parameters, porosity distributions and porosity coefficient on vibration frequencies of metal foam nanoscale plates have been examined.