• 동력기계공학회지
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• 제4권1호
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• pp.20-25
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• 2000

In this study, methods for the characteristics measurement of pneumatic elements using isothermal chamber, the methods for the flow rate and dynamic characteristic measurement of pneumatic control valve, are proposed. An isothermal chamber is a chamber in which the steel wool is stuffed and isothermal condition can almost be realized. Therefore, the instantaneous flow rate could be measured only from the pressure response using the state equation of gas. Effectiveness and simplicity of the proposed method are confirmed by comparing the measured results obtained by proposed methods with the methods defined JIS and the ISO standards.

• 농업과학연구
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• 제51권3호
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• pp.295-305
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• 2024

Due to the environment of irregular soil characteristic for agricultural fields, dynamic characteristic occurs in the tractor cabin during agricultural operations. Operator's fatigue is increased, and operation performance is decreased by these irregular environment conditions. This study was conducted to measure and analyze the dynamic characteristic of a tractor cabin, a major agriculture machinery, during agricultural operations. The specification of tractor used in the study was a 95 kW class tractor. To analyze the dynamic characteristics of the tractor cabin, the main agricultural operations, plow tillage and rotary tillage, were selected. To measure data of dynamic characteristic of the cabin, which continuously changes during operations, an Ellipse Series INS (inertia navigation system) with a built-in IMU (inertia measurement unit) was attached to the center of gravity of the cabin. During field test, the gear stages of plow tillage were B4 (4.3 km·h^-1) and B5 (5.6 km·h^-1), and the gear stages of rotary tillage were A3 (3.3 km·h^-1) and A4 (4.2 km·h^-1), which are the most commonly used. To analyze dynamic characteristic such as roll and pitch during operations according to the gear stages. As a result, the dynamic characteristics of pitch increased more than the dynamic characteristics of roll as the travel speed increased, and the dynamic characteristics of both agricultural operations were in the range of 2 to 5°.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.994-995
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• 2014

Supporting stiffness of seats is an important component affecting dynamic characteristics cognized by a passenger. To analyze dynamic characteristic of a seat for vehicles operating on various road conditions, the seat vibration from road irregularity should be understood and compared. In this study, the seat is analyzed as distributed supporting system. The dynamic stiffness is measured using masses. The characteristic of the seats is analyzed by measuring distributed dynamic stiffness. The distributed dynamic stiffness of the seat is estimated on various locations and the effects of each component such as spatial distribution, compression level and vibration amplitude are analyzed. The influence of seat cover, elastic support and flexible polyurethane foam on the measured stiffness was analyzed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.258-263
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• 2005

The nearest variety of the industrial world requires using the high precision and resolution positioning technology to do a semi-conductor, information field , and measurement field. It is especially important for the positioning technology that makes up a proper controller, is affected by the minimal heat and vibration, and can control a structurally generated non-linear friction factor to determine the efficiency of the system. The paper is to analyze the vibration characteristic according to the speed of linear motor and grasp the dynamic characteristic through the modal test and show the verification of the experimental result and design parameters by using FEM(Finite Element Method). Also, it shows the optimum standard analyzed the acceleration patterns of the moving part that lead to the vibration source in linear motor. It presents the analyzed dynamic of linear motor in compliance with a change of the non-linear factor.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.353-360
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• 1998

Dynamic measurements are used rather sparingly to determine the elastic moduli of rock cores and modulus values are not much utilized in design practice. The reason seems to result from the general perception that values obtained by dynamic measurement are much higher (about 10 times) than those determined statically. This paper presents results from dynamic and static tests on rock cores. The findings are : 1) elastic moduli can be consistently determined by laboratory seismic testing. 2) nonlear deformation characteristic of rock cores was tentatively proposed with variation in elastic modulus with strain.

• 연구논문집
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• 통권29호
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• pp.101-109
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• 1999

Presented in this paper is a new method of identifying the critical speed of rotor-bearing systems without actually reaching at the critical speed itself. Using the method, it is not only possible to calculate the critical speed by measuring a series of rotor responses at much lower rotating speeds away from and without reaching at the critical speeds but also the damping ratio and eccentricity of the system can be identified at the same time. Two types of test rotors were tested on the Rotor Dynamics Test Facility at the Rotordyn-amics Lab, KIMM, and the theory has been confirmed experimentally. The method can be adopted to monitor changes of the dynamic characteristics of critical rotating machinery before and after overhauls, repairs, exchanges of various parts, or to detect trends of direction of subtle changes in the dynamic characteristic parameters over a long periods of time.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.605-611
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• 2000

Presented in this paper is a new method of identifying the critical speed of rotor-bearing systems without actually reaching at the critical speed itself. Using the method, it is not only possible to calculate the critical speed by measuring a series of rotor responses at much lower rotating speeds away from and without reaching at the critical speeds but also the damping ratio and eccentricity of the system can be identified at the same time. Two types of test rotors were tested on the Rotor Dynamics Test Facility at the Rotordynamics Lab., KIMM, and the theory has been confirmed experimentally. The method can be adopted to monitor changes of the dynamic characteristics of critical rotating machinery before and after overhauls, repairs, exchanges of various parts, or to detect trends of direction of subtle changes in the dynamic characteristic parameters over a long periods of time.

• 전기전자학회논문지
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• 제22권4호
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• pp.907-915
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• 2018

본 논문에서는 저가형 적외선 거리 센서의 성능을 개선하는 방법을 제안한다. 적외선 거리 센서는 반사광의 강도를 측정하여 거리로 환산한다. 제안하는 방법은 센서의 감지 거리를 개선하고 다양한 조명환경에서도 강인하게 동작하도록 한다. 이는 센서의 특성곡선을 추출하고 이를 바탕으로 HDR(High Dynamic Range) 기법을 적용함으로써 가능해졌다. 적외선 입력의 세기와 노출 시간을 다양하게 변화시켜서 센서의 출력값을 획득하였고 이로부터 센서의 특성곡선을 추출하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1913-1917
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• 2000

SMD Equipment convey an electronic parts at high speed, then assemble parts into a circuit board, and it develop a long time-duration dynamic force to be caused by moving mass. Vibration problem to be caused by SMD Equipment have an effect on micro-meter level's precision production process, directly, and dynamic stability of building. In the cause of quantitatively access about its vibration problem, input information(or data) of structure dynamic analysis need accuracy information of dynamic load. Determination of Dynamic load is various kinds of method using experimental and theory. In this paper, we got dynamic load using direct measurement method. We expect that an study on the dynamic load characteristic of SMD can be used to Equipment development of low level vibration and basis information of structure dynamic analysis.

• 소음진동
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• 제6권6호
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• pp.727-733
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• 1996

Machines installed in various structures emit airborne sound and structureborne sound and are major source of noise and vibration. Especially when machines are installed upon a flexible foundation, most of noise and vibration are due to transmission of structureborne sound. Therefore, characterization and measurement of structureborne sound source level are necessary for controlling noise and vibration. But structureborne sound from vibrating machine is strongly coupled to the supportingstructure. This paper proposes the method of estimating the supporting sturcture's dynamic character- istic and structureborne sound source level for machine installed system without separating the machine, resilient mount and foundation.