• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.349-354
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• 2000

The modal analysis based on deformations is the method to drived dynamic responsed from superposition of natural frequency and mode shape. In order to free vibration analysis of the structures, Aluminum-made model is used in experiment. The dynamic characteristic of the structures are determined from acceleration measurements using impulse hammer. Experimenrt input and output signal are derive from impact hammer and the one accerometer. This paper present three methods for calculating the natural frequencies and mode shapes of the structure with theory value and finite element analysis, experiment. The results were good approximated about natural frequency and mode shape.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.320-325
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• 2004

The paper deals with the dynamic response of a cantilevered beam under a travelling mass with constant acceleration. Governing equations of motion taking into account all inertia effects of the travelling mass are derived by Galerkin's mode summation method, and Runge-Kutta integration method is applied to solve the differential equations. The effects of the speed, acceleration and the magnitude of the travelling mass on the response of the beam are fully investigated. A variety of numerical results allows us to draw important conclusions for structural design purposes.

• 대한기계학회논문집A
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• 제27권9호
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• pp.1486-1491
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• 2003

A modeling method for the modal analysis of a composite trapezoidal plate undergoing in-plane translational acceleration is presented in this paper. The equations of motion for the plate are derived and transformed into a dimensionless form. The effects of the inclination angles, fiber orientation angle and the acceleration on the modal characteristics of the plate are investigated.

• 한국철도학회논문집
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• 제10권5호
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• pp.607-612
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• 2007

본 논문에서는 도시철도 차량의 운전모드에 의한 레일마모 현상을 역행, 타행, 제동 세구간 별로 나누어 레일 마모 현상을 비교 분석하였고, 또한 ATO 로깅데이터에서 실제 운행한 속도데이터를 가속도와 감속도 데이터로 변환하여 열차의 가속도의 견인력과 감속도의 제동력에 의해 발생되는 레일마모량을 비교 분석한 결과로 통해 궤도 관리에 적용할 수 있는 방안을 제시하고자 한다.

• 한국자동차공학회논문집
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• 제2권6호
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• pp.9-17
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• 1994

In this study, a shifting algorithm of CVT was suggested for the two(2) driving modes : (1) power mode and (2) economy mode. Shifting algorithm must be obtained to make the engine run on the optimum operating line for the desired performance of the vehicle. Optimum operating lines of the engine were obtained by connecting the shortest way of the iso-power lines for the power mode and by connecting the shortest way of the BSFC curves for the economy mode. Also dynamic model of CVT vehicle was derived considering the throttle and the brake operation. By using the shifting algorithm and the CVT vehicle model, numerical simulations were performed to estimate the performance of CVT. Simulation results showed that comparing the performance of the conventional 4-speed automatic transmission, acceleration performance of the CVT vehicle was almost same with the AT vehicle for the power mode and the fuel economy of CVT was 14% superior than that of AT for the economy mode.

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권3호
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• pp.180-191
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• 2016

Purpose: The purpose of this study was to develop the accelerated life test method for Constant Electrical Potential Electrolysis gas sensor (CEPE gas sensor). Methods: The parts and modules of CEPE gas sensor were analyzed by using Reliability Block Diagram (RBD). Failure Mode and Effect Analysis (FMEA) and Quality Function Deployment (QFD) methods were performed for each part to determine the most affecting stress factor in its life cycle. The long term testing was conducted at three different dry heat levels and the acceleration factor was developed by using Arrhenius relationship. Conclusion: The acceleration factor for CEPE gas sensor was developed by using FMEA, QFD, and statistical analysis for its failure data. Also qualification tests were designed to meet the target life.

• Smart Structures and Systems
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• 제14권4호
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• pp.699-718
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• 2014

The indirect displacement estimation using acceleration and strain (IDEAS) method is extended to various types of beam structures beyond the previous validation on the prismatic or near-prismatic beams. By fusing different types of responses, the IDEAS method is able to estimate displacements containing pseudo-static components with high frequency noise to be significantly reduced. However, the concerns to the IDEAS method come from possible disagreement of the assumed sinusoidal mode shapes to the actual mode shapes, which allows the IDEAS method to be valid only for simply-supported prismatic beams and limits its applicability to real world problems. In this paper, the extension of the IDEAS method to the general types of beams is investigated by the mathematical formulation of the modal mapping matrix only for the monitored substructure, so-called monitoring span. The formulation particularly considers continuous and wide beams to extend the IDEAS method to general beam structures that reflect many real bridges. Numerical simulations using four types of beams with various irregularities are presented to show the effectiveness and accuracy of the IDEAS method in estimating displacements.

• 한국안전학회지
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• 제33권1호
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• pp.81-87
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• 2018

The seismic response, the natural frequencies and the mode shapes of an offshore wind turbine with twisted tripod substructure subject to various pile-ground interactions are discussed in this paper. The acceleration responses of the tower head by four historical earthquakes are presented as the seismic response, while the other loads are assumed as ambient loads. For the pile-ground interactions, the fixed, linear and nonlinear models are employed to simulate the interactions and the p-y, t-z and Q-z curves are utilized for the linear and nonlinear models. The curves are designed for stiff, medium and soft clays, and thus, the seven types of the pile-ground interactions are used to compare the seismic response, the acceleration of the tower head. The mode shapes are similar to each other for all types of pile-ground interactions. The natural frequencies, however, are almost same for the three clay types of the linear model, while the natural frequency of the fixed support model is quite different from that of the linear interaction model. The wind turbine with the fixed support model has the biggest magnitude of acceleration. In addition, the nonlinear model is more sensitive to the stiffness of clay than the linear pile-ground interaction model.

• 드라이브 ㆍ 컨트롤
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• 제19권3호
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• pp.32-38
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• 2022

The in-wheel drive gearbox for military special vehicles converts the high-speed & low-torque output generated by the electric servomotor, into low-speed & high-torque mechanical power. As the vehicle is remotely maneuvered in mountainous terrain, wet fields, rough terrain, etc., the gearbox must generate a maximum input speed exceeding 5,000 rpm, a maximum torque of 245 Nm, and MTBF of 9,600 km. The purpose of this study was to analyze the failure mode of the gearbox, to ensure the durability of the in-wheel drive gearbox. Also, the field load test data of the vehicle was analyzed, the acceleration durability test standards were established, the acceleration durability test was conducted, and the durability test results were analyzed as well.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권5호
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• pp.354-360
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• 1999

PCN-PZT piezoelectric acceleration sensors of annular shear mode voltage type were fabricated and their characteristics have been investigated. Field tests are also carried out. To avoid noise problems from the environmental conditions, acceleration sensors employed solid state micro-electronics for pre-amplifier. The calibration procedures based on the principle of the comparison method were adopted for investigating the characteristics of fabricated acceleration sensors. The voltage sensitivity and resonant frequency of fabricated acceleration sensors were 83mv/g, 23kHz, respectively. The lower and upper frequency limit were 4Hz and 9kHz, respectively. The variation of the voltage sensitivity showed 10% at $-406{\circ}C\; and\; 9%\; at\; 121^{\circ}C$ compared to that of reference temperature at $40^{\circ}C$.