• Title/Summary/Keyword: Super-element

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Simulations of time dependent temperature distributions of Super-ROM disk structure using finite element method (유한요소법을 이용한 Super-ROM 디스크 구조의 열 분포 해석)

  • Ahn, Duck-Won;You, Chun-Yeol
    • Transactions of the Society of Information Storage Systems
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    • v.1 no.2
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    • pp.132-136
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    • 2005
  • It is widely accepted that the reading mechanism of Super-RENS(super-resolution near field structure) and Super-ROM(super-resolution read only memory) is closely related with non-linear temperature dependent material properties such as refractive indices, phase change. Furthermore, the dynamic change of the temperature distribution also an essential part of reading mechanism of Super-RENS/ROM. Therefore, the knowledge of the temperature distribution as a function a time is one of the important keys to reveal the physics of reading mechanism in Super-RENS/ROM. We calculated time-dependent temperature distribution in a 3-dimensional Super-ROM disk structure when moving laser beam is irradiated. With a help of commercial software FEMLAB which employed finite element method, we simulated the temperature distribution of ROM structure whose pit diameter is 120-nm with 50-nm depth. Energy absorption by moving laser irradiation, time variations of heat transfer processes, heat fluxes, heat transfer ratios, and temperature distributions of the complicate 3-dimensional ROM structure have been obtained.

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Finite Element Stress Analysis of Coil Springs using a Multi-level Substructuring Method I : Spring Super Element (다단계 부분구조법을 이용한 코일스프링의 유한 요소 응력해석 I : 스프링 슈퍼요소)

  • Kim, Jin-Young;Huh, Hoon
    • Transactions of the Korean Society of Automotive Engineers
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    • v.8 no.2
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    • pp.138-150
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    • 2000
  • This study is concerned with computerized multi-level substructuring methods and stress analysis of coil springs. The purpose of substructuring methods is to reduce computing time and capacity of computer memory by multiple level reduction of the degrees of freedom in large size problems which are modeled by three dimensional continuum finite elements. In this paper, a super element has been developed for stress analysis of coil springs. The spring super element developed has been examined with tension and torsion simulation of cylindrical bars for demonstrating its validity. The result shows that the super element enhances the computing efficiency while it does not affect the accuracy of the results and it is ready for application to the coil spring analysis.

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Efficient Super-element Structural Vibration Analyses of a Large Wind-turbine Rotor Blade Considering Rotational and Aerodynamic Load Effects (회전 및 풍하중 가진 효과를 고려한 대형 풍력발전 로터의 효율적인 슈퍼요소 구조진동해석)

  • Kim, Dong-Man;Kim, Dong-Hyun;Park, Kang-Kyun;Kim, Yu-Sung
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.7
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    • pp.651-658
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    • 2009
  • In this study, computer applied engineering(CAE) techniques are fully used to efficiently conduct structural and dynamic analyses of a huge composite rotor blade using super-element. Computational fluid dynamics(CFD) is used to predict aerodynamic loads of the rotating wind-turbine blade. Structural vibration analysis is conducted based on the non-linear finite element method for composite laminates and multi-body dynamic simulation tools. Various numerical results are presented for comparison and the structural dynamic behaviors of the rotor blade are investigated herein.

Nonlinear seismic analysis of a super 13-element reinforced concrete beam-column joint model

  • Adom-Asamoah, Mark;Banahene, Jack Osei
    • Earthquakes and Structures
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    • v.11 no.5
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    • pp.905-924
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    • 2016
  • Several two-dimensional analytical beam column joint models with varying complexities have been proposed in quantifying joint flexibility during seismic vulnerability assessment of non-ductile reinforced concrete (RC) frames. Notable models are the single component rotational spring element and the super element joint model that can effectively capture the governing inelastic mechanisms under severe ground motions. Even though both models have been extensively calibrated and verified using quasi-static test of joint sub-assemblages, a comparative study of the inelastic seismic responses under nonlinear time history analysis (NTHA) of RC frames has not been thoroughly evaluated. This study employs three hypothetical case study RC frames subjected to increasing ground motion intensities to study their inherent variations. Results indicate that the super element joint model overestimates the transient drift ratio at the first story and becomes highly un-conservative by under-predicting the drift ratios at the roof level when compared to the single-component model and the conventional rigid joint assumption. In addition, between these story levels, a decline in the drift ratios is observed as the story level increased. However, from this limited study, there is no consistent evidence to suggest that care should be taken in selecting either a single or multi component joint model for seismic risk assessment of buildings when a global demand measure such as maximum inter-storey drift is employed in the seismic assessment framework.

A Study on Visual Characteristic & Evaluation of the Super Graphic of High-raised Apartment Housing (고층 아파트 외관 슈퍼그래픽의 시지각적 특성 및 평가 성향에 관한 연구)

  • 최석창;양소진;유창균;이청웅
    • Journal of the Korean housing association
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    • v.14 no.6
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    • pp.147-154
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    • 2003
  • This study examines and analyzes the current status, characteristics and properties of Super-Graphic as a visual element with Super Graphic designed on the wall of apartment housing, typifies them and explains the preference and evaluative structure by each type. The results of this study are as follows: According to color environment of Super-Graphic, N-tone colors are 21.4% and YR-tone colors are 14.5%. In the whole distribution, cold color tone is 41.4% and warm color tone is 37.2%. In the brightness, 72.9% of the entire Super Graphic use high brightness and in the saturation, 51.2% show low saturation, achromatic colors are 21.4% and high saturation is 16.5%. As a result of conducting SD test to analyze the preference of Super-Graphic, 'wonderful' is most negative variable, followed by 'heterogeneous', 'splendid', 'romantic' variety'. Positive variables are 'monotone', 'stable' and 'calm'. As a result of factor analysis to reveal the evaluative structure of Super Graphic image based on the above results, five factors including brightness, saturation, stability, harmony and ordered are extracted and it is considered that these are important variables to be reflected in designing Super Graphic in future.

Free transverse vibration of shear deformable super-elliptical plates

  • Altekin, Murat
    • Wind and Structures
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    • v.24 no.4
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    • pp.307-331
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    • 2017
  • Free transverse vibration of shear deformable super-elliptical plates with uniform thickness was studied based on Mindlin plate theory using finite element method. Quadrilateral isoparametric elements were used in the paper. Sensitivity analysis was made to determine the influence of the thickness, the aspect ratio, and the shape of the plate on the natural frequency. Accuracy of the results computed in the current study was validated by comparing them with the solutions available in the literature. The results reveal that the frequencies of clamped super-elliptical plates lie in the range bounded by elliptical and rectangular plates irrespective of the aspect ratio, and furthermore, the frequency decreases if the super-elliptical power increases. A similar trend was observed for simply supported plates with high aspect ratio. The free vibration response for the first and the second symmetric-antisymmetric (SA) modes were found to be different for high aspect ratio. The results reveal that using insufficient number of degrees of freedom results in finding a totally different relation between the super-elliptical power and the frequency.

A Numerical Method for Wave Reflection and Transmission Due to Local Non-Uniformities in Waveguides at High Frequencies (국부적 불연속을 가진 도파관의 고주파수 대역 파동 반사 및 투과 해석 기법)

  • Ryue, Jung-Soo
    • The Journal of the Acoustical Society of Korea
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    • v.29 no.5
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    • pp.314-324
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    • 2010
  • In waveguide structures, waves may be partially reflected by local non-uniformities. The effects of local non-uniformities has been previously investigated by means of a combined spectral element and finite element (SE/FE) method at relatively low frequencies. However, since the SE is formulated based on a beam theory, the SE/FE method is not appropriated for analysis at higher frequencies where complex deformation of the waveguide occurs. So it is necessary to extend this approach for high frequencies. For the wave propagation at higher frequencies, a combined spectral super element and finite element (SSE/FE) method is introduced in this paper. As an example of the application of this method, wave reflection and transmission due to a local defect in a rail are simulated at frequencies between 20kHz and 30kHz. Also numerical errors are evaluated by means of the conservation of the incident power.

Elastic Analysis of the Mode III Crack Problem (모드III 탄성 균열문제 해석에 대한 연구)

  • 김윤영;윤민수
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.19 no.4
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    • pp.941-949
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    • 1995
  • An efficient method based on analytic solutions is applied to solve anti-plane Mode III crack problems. The analytic technique developed earlier by the present authors for Laplace's equation in a simply-connected region is now extended to general Mode III crack problems. Unlike typical numerical methods which require fine meshing near crack tips, the present method divides the cracked bodies, typically non-convex or multiply-connected, into only a few super elements. In each super element, an element stiffness matrix, relating the series coefficients of the traction and displacement, is first formed. Then an assembly algorithm similar to that used in the finite elements, is first formed. Then an assembly algorithm similar to that used in the finite elements, is developed. A big advantage of the present method is that only the boundary conditions are to be satisfied in the solution procedure due to the use of analytic solutions. Several numerical results demonstrate the efficiency and accuracy of the present method.

Sectional forming analysis by membrane finite elements considering bending effects (굽힘효과를 고려한 박막 유한요소에 의한 단면 성형해석)

  • Kim, Jun-Bo;Lee, Gwang-Byeong;Keum, Yeong-Tak
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.22 no.3
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    • pp.493-503
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    • 1998
  • The sectional forming analysis considering bending effects from the geometrically deformed shape of two linear membrane finite elements(called super element) was performed under plane strain assumption for analyzing forming processes of an arbitrarily shaped draw-die. For the evaluation of bending effects, the bending equivalent forces are calculated from the bending moment computed using the changes in the interior angle at the middle node of super element, and are agumented to the membrane stretch forces. In order to verify the validity of the bending formulation, the simulation results for the stretch, draw, and bend sections were compared with membrane analysis results and measurements.