• Transactions of the Korean Society of Mechanical Engineers
• /
• v.6 no.4
• /
• pp.384-389
• /
• 1982

It is necessary that machine tool structures should be designed so that they will cause a minimum chance of machining chatter. In order to do this, a computer program package is developed utilizing Finite Element Method, modal flexibility and energy balance method. Validity of the program package is verified through computer simulation analysis and impulse test of a simplified machine tool structure.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2013.05a
• /
• pp.751-752
• /
• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1996.11a
• /
• pp.648-652
• /
• 1996

Grinding Center(GC)는 머시닝센터가 갖는 드릴링, 태핑 등의 절삭가공의 수행은 물론 주축의 고속화, 이송계의 고정밀화를 토대로 연삭숫돌의 절삭성 회복과 다듬질면의 거칠기를 확보하기 위한 기계로서 Dressing/Truing장치, 기상계측 장치, CNC기능을 구비하여 테이블과 공구간에 3차원의 상대운동을 시킴으로써 평면연삭, 내면연삭, 홈연삭, 캠연삭 등의 복잡한 형상의 연삭가공에 대해서도 공정을 집약화 할 수 있는 기계이다.(중략)

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2002.10a
• /
• pp.33-38
• /
• 2002

Dynamic analysis of laminated beams with a embedded damping layer under tension or compression axial load is investigated. Layer-Wise Zig-Zag Beam Theory and Interdependent Kinematic Relation using the governing equations of motion are incorporated to model the laminated beams with a damping layer and a corresponding beam zig-zag finite element is developed. Flexural frequencies and modal loss factors under tension or compression axial load are calculated based on Complex Eigenvalue Method. The effects of the axial tension and compression load on the frequencies and loss factors are discussed.

• Proceedings of the KSR Conference
• /
• 2005.11a
• /
• pp.1261-1267
• /
• 2005

At this paper Dynamic respones of bridges for the Korean high-speed railway are analyzed by a modal analysis. To control vibration of bridges, Tuned Mass Damper(TMD) that is passive type control device is used. Opimize and prove it. Newmark method is used for a numerical analysis. In case of vehicle is modeled for moving mass that considers the effects of the moving. Also this paper is assumped as the simple supported Bernoulli-Euler beam and considered two dimensional Interaction motion between vehicle and bridge.

• Structural Engineering and Mechanics
• /
• v.59 no.3
• /
• pp.455-473
• /
• 2016

Methods for the seismic demands evaluation of structures require iterative procedures. Many studies dealt with the development of different inelastic spectra with the aim to simplify the evaluation of inelastic deformations and performance of structures. Recently, the concept of inelastic spectra has been adopted in the global scheme of the Performance-Based Seismic Design (PBSD) through Capacity-Spectrum Method (CSM). For instance, the Modal Pushover Analysis (MPA) has been proved to provide accurate results for inelastic buildings to a similar degree of accuracy than the Response Spectrum Analysis (RSA) in estimating peak response for elastic buildings. In this paper, a simplified nonlinear procedure for evaluation of the seismic demand of structures is proposed with its applicability to multi-degree-of-freedom (MDOF) systems. The basic concept is to write the equation of motion of (MDOF) system into series of normal modes based on an inelastic modal decomposition in terms of ductility factor. The accuracy of the proposed procedure is verified against the Nonlinear Time History Analysis (NL-THA) results and Uncoupled Modal Response History Analysis (UMRHA) of a 9-story steel building subjected to El-Centro 1940 (N/S) as a first application. The comparison shows that the new theoretical approach is capable to provide accurate peak response with those obtained when using the NL-THA analysis. After that, a simplified nonlinear spectral analysis is proposed and illustrated by examples in order to describe inelastic response spectra and to relate it to the capacity curve (Pushover curve) by a new parameter of control, called normalized yield strength coefficient (${\eta}$). In the second application, the proposed procedure is verified against the NL-THA analysis results of two buildings for 80 selected real ground motions.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.29 no.6
• /
• pp.539-545
• /
• 2016

UPS system in the liquefied natural gas(LNG) receiving terminal is one of the fundamental equipment that need to sustain operation during earthquake. In this study, modal identification test of UPS system was performed based on IEEE Std. 693-2005 and natural frequencies and modal damping, mode shapes had been identified. In addition, tri-axial time history test was performed to check the behavior and stress of the equipment during earthquake. Eigenvalue analysis was performed and analysis model was modified by reflecting the results of the test. Static analysis by dead weight and response spectrum analysis were performed to compare the combined stresses with the stress results of test. Dynamic characteristics and combined stresses under seismic load condition of the improved analysis model were similar to the test results and in this regard the compatibility was proved.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2007.11a
• /
• pp.1284-1287
• /
• 2007

Recently, the need for slim type optical disk drive(ODD) has increased with popularization of lightweight notebook. Because of its lightweight and small structure, slim type ODD has low structural stiffness and it is weak to high-speed disk vibration. In this paper, Finite Element(FE) Model of slim type ODD is constructed and verified by experimental modal analysis. Additionally, sensitivity analysis is performed about structural parameters. As a result of sensitivity analysis, improved characteristic is verified by experiments using a sample of new model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2008.11a
• /
• pp.602-603
• /
• 2008

The design modification of problematic component in a given vibration path is disallowed in order to sacrifice other performances such as ride comport or handling of a vehicle. For this, the paper presents a new contribution analysis based on transmissibility ratio (TR) of acceleration in a definite vibration path to find a proper candidate for design modification. The new contribution analysis is based on the fact that the sensitivity of TR over a small design change is inversely proportional to the magnitude of TR. The new methodology can significantly relieve efforts of time-consumming modal analysis for detail modal information. The theory of proposed contribution analysis is simulated with five-degree-of-freedom open vibration path and confirms that the contribution result is well matched with the variance of TR over a dynamic change on a vibration path.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.36 no.1
• /
• pp.117-124
• /
• 2012

In this paper, an analysis of the joint that transmits power from the blades to the generator is performed using the FEM (finite element method). The mode shapes and natural frequencies were extracted using experimental modal analysis in order to establish the FEM model. Then, the model was verified by comparing the mode shapes and natural frequencies to those obtained from the ANSYS modal analysis. Dynamic stress analysis was performed at the rated and limited wind speeds considering the wind load and gravity.