• 한국재난정보학회 논문집
• /
• 제12권1호
• /
• pp.69-73
• /
• 2016

선점법에 대한 연구가 유한요소법처럼 범용화 되어 있지 않아 적용성과 유효성에 대한 연구가 필요하다. 본 연구에서는 범용적으로 사용된 유한요소법과 비교하여 비선형 진동문제에 대한 선점법의 적용성과 유효성을 확인한다. 또한, 선점법을 미분방정식 조건에 따라 내부법, 경계법, 혼합법으로 나누어 비선형 응답 곡선을 유한요소법 결과와 비교하여 동적 특성 문제의 선점법 적용성과 유효성을 확인한다.

• Journal of the Korean Society for Industrial and Applied Mathematics
• /
• 제20권1호
• /
• pp.17-35
• /
• 2016

In this study, the dynamic behaviour of a rotating Timoshenko beam when under the actions of a variable magnitude load moving at non-uniform speed is carried out. The effect of cross-sectional dimension and damping on the flexural motions of the elastic beam was neglected. The coupled second order partial differential equations incorporating the effects of rotary and gyroscopic moment describing the motions of the beam was scrutinized in order to obtain the expression for the dynamic deflection and rotation of the vibrating system using an elegant technique called Galerkin's Method. Analyses of the solutions obtained were carried out and various results were displayed in plotted curve. It was found that the response amplitude of the simply supported beam increases with an increase in the value of the foundation reaction modulus. Effects of other vital structural parameters were also established.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2005년도 춘계학술대회
• /
• pp.64-67
• /
• 2005

A vibration monitoring system for a small size wind turbine (WIT) is established and operated. The monitoring system consists of monolithic integrated chip accelerometer for vibration monitoring, anemometers for wind data acquisition and auxiliary sensors for atmospheric data. Using the monitoring system, vibration response of a 6kW stand alone WIT generator is investigated. Acceleration data of the WIT tower under various operation condition is acquired in real time using LabVIEW and the data are remotely transferred from the test site to the laboratory in school by internet. Vibration response characteristics of the tower structure are diagnosed in the aspect of stability of W/T. Wind data and electrical power performance are also investigated with the stability problem.

• 제어로봇시스템학회논문지
• /
• 제8권4호
• /
• pp.308-312
• /
• 2002

To determine the natural frequencies and damping ratios of composite laminated plates, we present an officient modal parameter estimation technique by developing residual spectrum based structural system reconstruction. The modal parameters can be estimated from poles and residues of the system transfer functions, derived from the state space system matrices. From vibration tests on cross-ply and angle-ply composite laminates, the natural frequencies and damping ratios can be estimated using the modal coordinates of the structural dynamic system reconstructed from the experimental frequency response functions. These results are compared with those of finite element analysis and single-degree-of-freedom curve fitting.

• 한국통신학회논문지
• /
• 제23권5호
• /
• pp.1372-1383
• /
• 1998

본 논문에서 수행된 DFB(distributed feedback)-LD(laser diode)의 DC와 AC 특성 분석을 위한 모델링은 레이저 다이오드 공진기 내의 spatial hole burning과 $\lambda$/4 위상천이 된 회절 격자의 영향을 고려한 것으로서 DC특성 분석을 위한 시뮬레이션을 통하여 공진기내의 광파워 분포와 캐리어 밀도 분포 그리고 광-전류 곡선등을 얻었으며, AC 특성 분석을 위한 시뮬레이션으로부터는 비교적 정확한 IM 응답과 FM의 위상과 크기 응답을 얻었다.

• Journal of Information Display
• /
• 제12권3호
• /
• pp.129-134
• /
• 2011

The universal current reversal method is used for the simultaneous measurement of response time (${\tau}$), azimuthal angle (${\varphi}_o$), spontaneous polarization ($P_S$), and rotational viscosity (${\gamma}_{\varphi}$) of two ferroelectric liquid crystals (FLCs). The application of AC field in FLCs results in reorientational current, which is further analyzed to obtain various parameters. The variation in the parameters with temperature follows the typical trend predicted by the theory. The theoretical curve fits well into the experimental data. Its comparison with traditional current reversal method is confirmed to address certain limitations of that method.

• 한국농공학회지
• /
• 제45권5호
• /
• pp.110-116
• /
• 2003

A catchment modelling system is the summation of the numerous hydrologic, hydraulic and other process models necessary to simulate the response of a catchment to a storm event. Differences between the recorded catchment response and that predicted by a catchment modelling system can arise from structural errors within the catchment modelling system, evaluation errors in the control parameters, or measurement errors in the recorded data being used to assess the reliability of the evaluation of the control parameters. Presented herein is an investigation of the potential measurement errors within the recorded information, which was considered to occur from instrument error in the ultra sonic flow monitor. This investigation was undertaken using three available rating curves at the Musgrave Avenue Stormwater System in Centennial Park, Sydney, developed by Abustan (1997), Water Board (1994), and using Manning's equation.

• Structural Engineering and Mechanics
• /
• 제25권1호
• /
• pp.75-89
• /
• 2007

Post-earthquake reconnaissance and experimental research indicate that squat reinforced concrete (RC) columns in existing buildings or bridge piers are vulnerable to non-ductile shear failure. Recently, several experimental studies were conducted to investigate upgrading the shear resistance capacity of such columns in order to modify their failure mode to ductile one. Among these upgrading methods is the use of fibre-reinforced polymer (FRP) jackets. One of the preferred analytical tools to simulate the response of frame structures to earthquake loading is the lumped plasticity macromodels due to their computational efficiency and reasonable accuracy. In these models, the columns' nonlinear response is lumped at its ends. The most important input data for such type of models is the element's lateral force-displacement backbone curve. The objective of this study is to verify an analytical method to predict the lateral force-displacement ductility relationship of axially and laterally loaded rectangular RC squat columns retrofitted with FRP composites. The predicted relationship showed good accuracy when compared with tests available in the literature.

• Journal of Astronomy and Space Sciences
• /
• 제17권1호
• /
• pp.99-106
• /
• 2000

When a deployed probe is biased by a high positive potential during a space experiment, the payload is induced to a negative voltage in order to balance the total current in the whole system. The return currents are due to the responding ions and secondary electrons on the payload surface. In order to understand the current collection mechanism, the process was simulated with a combination of resistor, inductor, and capacitor in SPICE program which was equivalent to the background plasma sheath. The simulation results were compared with experimental results from SPEAR-3 (Space Power Experiment Aboard Rocket-3). The return current curve in the simulation was compatible to the experimental result, and the simulation helped to predict the transient plasma response to a high voltage during the plasma sheath formation.

• 한국전기전자재료학회논문지
• /
• 제18권10호
• /
• pp.924-928
• /
• 2005

We synthesized the two types of photoalignment material of high thermal resistance with hydroxyl aromatic polyimide, and studied the liquid crystal (LC) aligning capabilities on the photopolymer layers. Also, electro-optical (EO) performances for the twisted-nematic (TN)-liquid crystal display (LCD) photoaligned with linearly polarized UV exposure were investigated. A good LC alignment with UV exposure on the two types of photopolymer surface can be obtained. The Voltage-transmittance (V-T) curve in the photoaligned TN cell with UV exposure was different from two type. The response time of photoaligned TN cell was measured about 21 ms in two alkyl chain and about 15 ms in four alkyl chain.