• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2003년도 춘계학술대회 논문집
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• pp.494-499
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• 2003

This paper concerns the static, dynamic and thermal characteristics analysis of a high-speed spindle system for horizontal machining centers with 45mm x50,000rpm. The spindle system is designed based on the angular contact ceramic ball bearings, built-in motor, oil-air lubrication method and oil jacket cooling method. The structural and thermal analysis models of spindle system are constructed by the finite element method. The static and dynamic characteristics are estimated based on the static deformation, modal parameter, mode shape and frequency response function, and the thermal characteristics are estimated based on the temperature rise, temperature distribution and thermal deformation. The analysis results illustrate that the designed spindle system has excellent structural and thermal stabilities

• International Journal of Naval Architecture and Ocean Engineering
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• 제10권4호
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• pp.508-519
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• 2018

In order to design the hull form of an underwater vehicle in the conceptual design phase, the dynamic characteristics depending on the hull form parameters should be identified. Course-keeping stability, turning ability, yaw-checking ability, and mission competence are set to be the indices of the dynamic characteristics, and the geometric parameters for the bare hull and rudder are set to be the hull form design parameters. The total sensitivity of the dynamic characteristics with respect to the hull form parameters is calculated by the chain rule of the partial sensitivity of the dynamic characteristics with respect to the hydrodynamic coefficients, and the partial sensitivity of the hydrodynamic coefficients with respect to the hull form parameters. Based on the sensitivity analysis, important hull form parameters are selected, and those optimal values to satisfy the required intercept time of mission competence of a specific underwater vehicle and turning rate are estimated.

• 한국정밀공학회지
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• 제8권2호
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• pp.57-68
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• 1991

In this study, to analyse the dynamic characteristics of a machine-tool spindle system, the spindle is mathematically represented by a Timoshenko beam including the internal damping of beam material, and each bearing by four bearing coefficients; stiffness and damping coefficients in moment and radial directions. And the dynamic compliance of the system is calculated by introducing the transfer matrix method, and the complex modal analysis method has been applied for the modal parameter identification. The influence of the bearing coefficients, material damping factor and bearing span on the dynamic characteristics of the system is parametrically examined.

• International Journal of Reliability and Applications
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• 제17권2호
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• pp.137-147
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• 2016

The engine mount of a car subjected to a pre-load related to the weight of the engine, and acts to insulate the vibration coming from the engine by moving on large or small displacement depending on the driving condition of the car. The vibration insulation of the engine mount is an effect obtained by dissipating the mechanical energy into heat by the viscosity characteristic of the rubber and the microscopic behavior of the additive carbon black. Therefore, dynamic stiffness from the intrinsic properties of rubber filled with carbon black at the design stage is an important design consideration. In this paper, we introduced a hyper-elastic, visco-elastic and elasto-plastic model to predict the dynamic characteristics of rubber, and developed a fitting program to determine the material model parameters using MATLAB. The dynamic characteristics analysis of the rubber insulator of the ACTIVE MOUNT was carried out by using MSC.MARC nonlinear structural analysis software, which provides the dynamic characteristics material model. The analysis results were compared with the dynamic characteristics test results of the rubber insulator, which is one of the active mount components, and the analysis results were confirmed to be valid.

• Structural Engineering and Mechanics
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• 제74권1호
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• pp.121-128
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• 2020

This paper presents an experimental study on the dynamic characteristics of infilled reinforced concrete (RC) frames. A 1/3-scaled, one-bay, three-storey RC frame was produced and tested by using operational modal analysis (OMA). The experiments were performed on five specimens: one reference frame with no infill walls and four frames with infill walls. The RC frame systems included infill walls made of hollow clay brick, which were constructed in four different patterns. The dynamic characteristics of the patterns, including the frequency, mode shapes and damping ratios in the in-plane direction, were obtained by 6 accelerometers. Twenty-minute records under ambient vibration were collected for each model, and the dynamic characteristics were determined using the ambient vibration testing and modal identification software (ARTeMIS). The experimental studies showed that the infill walls significantly affected the frequency value, rigidity and damping ratio of the RC frame system.

• 소음진동
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• 제6권4호
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• pp.447-456
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• 1996

Dynamic characteristics of the bell-type structure including acoustic effects and transient dynamic problems were analyzed numerically. Natural frequencies, mode shapes and transient dynamic analysis used the finite element method with 3-D general shell element. Mode shapes and stress distributions of transient dynamic analysis were expressed by computer graphics. The method using this study was evaluated by comparision of theoretical results at reference papers(14), (15) and the experimental test using Fast Fourier Transform analyzer. Vibrational modes governing acoustic characteristics of the typical bell-type structure depended on the first flexural mode(4-0 mode) and the second flexural mode(6-0 mode). Asymmetric effects by Dangiwas, acoustic holes gave rise to beat frequencies, and the Dangjwa was found to be most effective. When impact load acted on the bell, stress concentration occured at the rim part of bell. It was found that the bell type structure should be designed thickly at the rim part in order to prevent impact load from stress concentration.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.808_809
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• 2009

This paper deals with the dynamic characteristic analysis on Linear Induction Motor(LIM) considering load conditions. The analysis on the electromagnetic characteristics is processed to derive circuit parameters, and dynamic modeling for the analysis is performed considering load conditions for speed and thrust dynamic characteristics.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.277-280
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• 2014

Recently, military vehicles that are being driven are equipped with a lot of electronic devices. The military vehicles are easily exposed to impact. Thus, they have to be designed robustly to ensure that the stability of the vehicle and the electronic equipment. In order to design the vehicles efficiently, the dynamic characteristics of a military vehicle have to be identified exactly. The main frame has a significant role to the dynamic characteristics of the vehicle. Thus, this research was progressed mainly with the frame. By carrying out road tests, the characteristics could be identified. Also, based on the characteristics, we constructed FE model of the frame and performed the analysis of the dynamic characteristics of the vehicle.

• 설비공학논문집
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• 제15권6호
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• pp.480-488
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• 2003

The purpose of this research Is to derive the principal design parameters governing the dynamic characteristics of the high response flow control servo valve. For this purpose, a numerical modeling of the servo valve system and a parameter sensitivity analysis to a frequency response characteristics was peformed. As a result of these analysis, a basis for improvement of a dynamic characteristics of servo valve was arranged.

• 터널과지하공간
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• 제16권5호
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• pp.394-404
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• 2006

암반구조물의 동적 거동은 구조물이 위치하는 동적 물성과 입력지진파의 특성에 따라 크게 다르며, 절리군이 발달한 암반은 블록의 역학적인 특성과 함께 불연속면의 구조적, 역학적 특성에 따라 다르다. 본 연구에서는 불연속체 해석 기법인 UDEC을 이용하여 지하구조물 주변에 발달한 불연속체의 구조적인 특징에 따라 변화하는 암반의 동적 거동을 평가하고, 이를 연속체 해석 기법인 $FLAC^{2D}$의 결과와 비교를 통해 절리 암반의 지진에 대한 동적 거동의 타당성을 비교 검토하였다. 그 결과, 불연속체가 고려된 해석 결과는 절리의 거동에 의한 영향으로 구조적인 형상에 따른 변화가 나타났으며, 연속체 해석 결과는 불연속체 해석 결과에 비해 과다 평가되는 것으로 나타났다.