• 한국포장학회지
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• 제9권1호
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• pp.7-10
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• 2003

This study was carried out to investigate vibration shock of electric appliances during transport. Microwave oven, TV, washing machine and refrigerator were singled out as the study items. Transport courses were selected as follow ; an expressway between Kumi and Seoul for TV, an expressway between Kwangju and Seoul for microwave oven and washing machine, a national road between Inchon and Seoul for refrigerator. the values of vibration shock were measured to be ${\sim}3G$ on the national road and 1G on the expressway for up and down direction, ${\sim}0.5G$ on the national road and expressway for back and forth direction and ${\sim}0.8G$ on the national road and expressway for right and left direction. There was no damage during transport. These values were corresponding to grade II of KS A 1026 (General Rules of Performance Testing for Packaged Freights).

• 한국정밀공학회지
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• 제10권3호
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• pp.191-197
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• 1993

In this paper, experimental studies are mainly carried out for the evaluation of precision cutting performance of a machine tool spincle running at high speed with the low load, in consideration of the bending vibration characteristics. As a result a process in presented for the practical application in the machine tools industry to evaluate the cutting performance in design stage of spindles.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.848-851
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• 2005

ATM(Automated-feller Machine) is a machine that receives and pays money directly. The double bill detector (DBD) module of an ATM detects double bill from its thickness. In this paper, the dynamic behavior of the DBD was analyzed numerically and experimentally. The moment of inertia of the double bill lever and the spring constant were measured respectively. And the displacements of the ]ever was measured experimentally. The measured dynamic behaviors were simulated numerically using vector equation. Through the analysis, the design factors were found to make a fast and reliable new ATM machine.

• 소음진동
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• 제4권4호
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• pp.459-467
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• 1994

Various maintenance programs and techniques have been implemented for roating machineries, since machines were invented for commerical use. The earliest type of maintenance was run-to-failure, where the machine was run until a fault caused to fail in service. It was obviously an expensive approach due to the unpredictability of the machine condition. Another type is the periodic maintenance, where machines are disassembled and overhauled on regular schedules. With the advent of reliable data collectors including FFT analyzer and developing of versatile supporting software such as ExpertALERT system, the predictive maintenance is known to be the most feasible maintenance type these days. The vibration analysis enables for a maintenance crew to find the exact cause of fault on a machine and to make a proper maintenance schedule with a trend analysis. The predicitive maintenance is considered to be the most important part of pro-active maintenance.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.253-256
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• 1997

In this study, we developed a portable device which monitors and analyzes a vibration signal happened to machines. This device is based on PDA which is smaller thant a palm of the hand, but it has powerful computing ability as much s a computer with 100MHz CPU and an operating system called Windows CE. As a preprocess for a diagnosis of a rotating machine, training artificial neural network based on PC is performed, and the device will diagnose the condition of a rotating machine using weight values as a result of the training ANN.

• Journal of Mechanical Science and Technology
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• 제19권6호
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• pp.1243-1252
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• 2005

This paper describes a new digital signal processor (DSP) imbalance measurement system dedicated to real-time vibration analysis on rotating machine. To accomplish real-time analysis, the vibration signals are on-line acquired and processed to analyze the mass imbalance and phase position. This is achieved through the use of FFT and Lissajous diagram. The method followed to analyze the mass imbalance with the chosen hardware and software solutions are described in detail in this paper. Several experimental tests demonstrate the efficiency and accuracy in imbalance analysis performance of the DSP system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1149-1153
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• 2000

All critical equipment installed aboard naval ships and submarines is required to be shock-qualified by tests on the MIL-S-901 shock test machines where testing is practical. The intent of the shock requirements is to produce combat vessels which are resistant to the underwater explosion weapon attack. To efficiently design equipment for passing a series of shock tests, the shock environment of the shock test machine should be clearly identified. In this paper, the shock characteristics of the MIL-S-901 Medium Weight Shock Machine(MWSM) are reviewed, based on the existing test data. An analytical model for the MWSM is also discussed.

• 소음진동
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• 제8권2호
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• pp.306-312
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• 1998

This paper proposes a method for estimating the vibrational power supplied by a machine that generates excitation force to its supporting structure via the coupling points. The basis of the method is that the vibrational power can be calculated using the mechanical impedance and the velocity at the coupling points on the supporting structure. First, a method is described to estimate the mobilities at the coupling points when the machine is not separable from the supporting structure, then the vibrational power is calculated using the estimated mobilities and measured velocities at the coupling points. The mobilities are estimated from the result of impulsive testing of the coupled structure. The method is investigated using an experimental model. The estimated and measured values of the mobilities and the vibrational power are compared. It is shown that the estimated values agree well with the measured values.

• 제어로봇시스템학회논문지
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• 제18권12호
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• pp.1090-1095
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• 2012

In this paper, we propose a model-based fault diagnosis method applied to vibration data. The fault detection is performed by comparing estimated parameters with normal parameters and deciding if the observed changes can be explained satisfactorily in terms of noise or undermodelling. The key feature of this method is that it accounts for the effects of noise and model mismatch. And we aslo design a classifier for the fault isolation by applying the multiclass SVM (Support Vector Machine) to the estimated parameters. The proposed fault detection and isolation methods are applied to an engine vibration data to show a good performance. The proposed fault detection method is compared with a signal-based fault detection method through a performance analysis.

• Smart Structures and Systems
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• 제2권1호
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• pp.47-60
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• 2006

Bi-spectrum is a tool in the signal processing for identification of non-linear dynamic behvaiour in systems, and well-known for stationary system where components are non-linearly interacting. Breathing of a crack during shaft rotation is also exhibits a non-linear behaviour. The crack is known to generate 2X (twice the machine RPM) and higher harmonics in addition to 1X component in the shaft response during its rotation. Misaligned shaft also shows similar such feature as a crack in a shaft. The bi-spectrum method has now been applied on a small rotating rig to observe its features. The bi-spectrum results are found to be encouraging to distinguish these faults based on few experiments conducted on a small rig. The results are presented here.