• 정보저장시스템학회논문집
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• 제8권1호
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• pp.22-26
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• 2012

Optical disk drives (ODDs) are subjected to vibrations caused by the high-speed rotation of the optical disk, and these vibrations can be excessive and reduce the read/write performance. Elastic rubber mounts with cushioning materials are often used to minimize these problems. In this paper, the source of vibrations was identified by experimental modal tests and high-speed photography. Structural modifications were made based on a lumped parameter model and a finite element model.

• 한국소음진동공학회논문집
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• 제19권12호
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• pp.1281-1288
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• 2009

Variation of dynamic characteristics of a low pressure turbine blade with crack length is studied in this paper via both experiments and finite element model. Since most of the turbine blades used in domestic power plants are imported from abroad, it is necessary to understand their dynamic behavior in advance. When experimentally obtained natural frequencies and mode shapes are compared with those from FEM results, they are close to each other in their magnitude. Then, it is more feasible to use finite element model for analyzing the dynamic characteristics of a blade under various operation conditions (rotation speed, temperature, etc) as well as with a crack in the blade.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 B
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• pp.678-680
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• 2000

We designed and manufactured DSPSRM using the usual output power equation of rotating machine. And the sinusoidaly approximated torque characteristics are achieved by 3D finite element analysis. Also, We calculated average torque per rotation using approximated torque data, calculated by 3D finite element analysis. On this paper, We manufacture torque-meter set and measure the torque characteristic of DSPSRM.

• Structural Engineering and Mechanics
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• 제38권5호
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• pp.549-571
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• 2011

This paper presents analytical solutions for skewed thick plates under transverse loading that have previously been unreported in the literature. The thick plate solution is obtained in a framework of an oblique coordinate system. The governing equation is first derived in the oblique coordinate system, and the solution is obtained using deflection and rotation as partial derivatives of a potential function developed in this research. The solution technique is applied to three illustrative application examples, and the results are compared with numerical solutions in the literature and those derived from the commercial finite element analysis package ANSYS 11. These results are in excellent agreement. The present solution may also be used to model skewed structures such as skewed bridges, to facilitate efficient routine design or evaluation analyses, and to form special elements for finite element analysis. At the same time, the analytical solution developed in this research could be used to develop methods to address post-buckling and dynamic problems.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.482-487
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• 2001

Time responses of a flexible spinning disk of which axis of symmetry is misaligned with the axis of rotation are analyzed in a numerical manner. Equations of motions are derived by Hamilton's principle based on Kirchhoff plate theory and von-Karman strain theory, and the equations are discretized by finite element method. In obtaining the time responses, Generalized-$\alpha$ method is used to solve the equations. Based on the result, the effects of the misalignment are analyzed on the vibration characteristics of a spinning disk.

• 한국정밀공학회지
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• 제22권6호
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• pp.47-54
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• 2005

A dangerous event occurred at the field industry and mechanical system. At developed by SUNGGOKNANOTECH corp. a R-L clutches of a small and high capacity serves safety device from a variety environment of mechanical system, it permits transmission of driving torque from input to output shaft in both directions of rotation, but restrains any feedback torque of the driven load from rotating the output shaft in either direction. This study was carried out to demonstrate through finite element method and durability estimation for safety of the R-L clutches without sliding during the engagement process. As results, we organized about endurance test method when applied rated torque.

• 융복합기술연구소 논문집
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• 제3권2호
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• pp.17-21
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• 2013

Hot cross wedge rolling process as an incremental forming has many advantages such as the material usage, the short process time, the automatic equipment line and the low forming load. However, it occurs some defects such as the surface groove, the axis warping and the Mannesmann hole. In this paper, the defect of the Mannesmann hole was carried out. Finite element analysis was utilized to reveal the stress distribution, the rotation of the specimen and the change of section profile. Cross wedge rolling experiment was also conducted on the generation of the Mannesmann hole. It was demonstrated according to the spreading angle with respect to the various types of material. In the view point of metal flow, the smaller forming angle and the larger spreading angle increase opportunities of the defect hole generations.

• Structural Engineering and Mechanics
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• 제69권4호
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• pp.427-437
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• 2019

In this study, an alternative solution procedure presented by using variational methods for analysis of shear deformable functionally graded material (FGM) beams with mixed formulation. By using the advantages of $G{\hat{a}}teaux$ differential approaches, a refined complex general functional and boundary conditions which comprises seven independent variables such as displacement, rotation, bending moment and higher-order bending moment, shear force and higher-order shear force, is derived for general thick-thin FGM beams via shear deformation beam theories. The mixed-finite element method (FEM) is employed to obtain a beam element which have a 2-nodes and total fourteen degrees-of-freedoms. A computer program is written to execute the analyses for the present study. The numerical results of analyses obtained for different boundary conditions are presented and compared with results available in the literature.

• Computers and Concrete
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• 제33권3호
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• pp.265-273
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• 2024

Predicting fracture properties requires an understanding of structural failure behaviour in relation to specimen type, dimension, and notch length. Facture properties are evaluated using various testing methods, wedge splitting test being one of them. The wedge splitting test was numerically modelled three dimensionally using the finite element method on self compacting concrete specimens with varied specimen and notch depths in the current work. The load - Crack mouth opening displacement curves and the angle of rotation with respect to notch opening till failure are used to assess the fracture properties. Furthermore, based on the simulation results, failure curve was built to forecast the fracture behaviour of self-compacting concrete. The fracture failure curve revealed that the failure was quasi-brittle in character, conforming to non-linear elastic properties for all specimen depth and notch depth combinations.

• 한국분말재료학회지
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• 제22권1호
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• pp.6-9
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• 2015

In this study, the behavior of densification of copper powders during high-pressure torsion (HPT) at room temperature is investigated using the finite element method. The simulation results show that the center of the workpiece is the first to reach the true density of copper during the compressive stage because the pressure is higher at the center than the periphery. Subsequently, whole workpiece reaches true density after compression due to the high pressure. In addition, the effective strain is increased along the radius during torsional stage. After one rotation, the periphery shows that the effective strain is increased up to 25, which is extensive deformation. These high pressure and severe strain do not only play a key role in consolidation of copper powders but also make the matrix harder by grain refinement.