• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1401-1409
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• 2007

This paper presents a detecting technique for the improvement in quality by appling the various vibrational characteristics theory. The object of this study is to objectively point out faulty gear by developing the program which can be used to analyze and predict the vibrational characteristics caused by gear wear, deformation and nick of auto-transmission. The fault detection methods by vibrational signal analysis of gear have been progressed in the various fields of industry. These methods have the advantage of being easy to attach the accelerometer without discontinuance of the structure. But not all the methods are efficient for finding early faults. So in the thesis, we completed development of the inspection system of vibration by appling the most efficient detecting methods and verified the system's reliability through experiments.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 제35회 춘계학술대회
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• pp.53-62
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• 2002

Condition monitoring plays a vital role since it sustains reliable operation of industrial plants and machinery in the pursuit of economic whole life operation. In order to achieve this goal, it is needed to monitor various parameters of mechanical system such as vibration, wear, temperature and etc., and finally to diagnosis the root causes of any possible abnormal machine condition. In this work, a machine failure caused by mechanical looseness was experimentally simulated and on-line measurement of the vibration, wear and temperature were simultaneously measured. For the quantitative analyses of machine wear, several statistical parameters of the wear particle size distribution were obtained through the center moment method of the Weibull distribution function, and they were compared to vibrational characteristics. Results showed that the wear and vibrational characteristics did not reveal a strong correlation each other in a loosely supported proceeding bearing.

• Journal of Advanced Marine Engineering and Technology
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• 제26권1호
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• pp.48-58
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• 2002

There is a purpose of this study for the proposal of the optimum technique utilized for the vibration design initial step. The stiffened plate structure for the ship hull is made for analysis model. To begin with, dynamic characteristics of stiffened plate structure is analysed using FEM. Main vibrational mode of the structure is decided in the analytical result of FEM. The simplified equation on the natural frequency of the main vibrational mode is induced. Next, sensitivity analysis is carried out using the simplified equation, and rate of change of dynamic characteristics is calculated. Then, amount of design variable is calculated using this sensitivity value and optimum structural modification method. The change of natural frequency is made to be an objective function. Thickness of panel, cross section moment of stiffener and girder become a design variable. The validity of the optimization method using simplified equation is examined. It is shown that the result effective in the optimum modification for natural frequency of the stiffened plate structure.

• 한국소음진동공학회논문집
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• 제19권3호
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• pp.268-273
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• 2009

The roller bearings play an important role not only sustain radial or axial load of system, but carry out a rotatory movement as a various operating conditions. They happen that incipient faults which were caused by excessive load, manufacturing or assembling process's errors and many other reasons are created. The bearing faults make noise and vibration by a continuous collision of rotatory components, which can lower the quality and stability of auto-transmission. Therefore, it is important to detect the early fault as soon as possible. This paper presents a detecting method for the improvement in quality by developing the program which can be used to analyze and predict the vibrational characteristics caused by roller bearing faults. We completed development of the inspection system of vibration by applying the most efficient detecting methods and verified the system's reliability through experiments.

• 한국소음진동공학회논문집
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• 제18권1호
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• pp.47-56
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• 2008

This paper presents a detecting technique for the improvement in quality by appling the various vibrational characteristics theory. The object of this study is to objectively point out faulty gear by developing the program which can be used to analyze and predict the vibrational characteristics caused by gear wear, deformation and nick of auto-transmission. The fault detection methods by vibrational signal analysis of gear have been progressed in the various fields of industry. These methods have the advantage of being easy to attach the accelerometer without discontinuance of the structure. But not all the methods are efficient for finding early faults. So in the thesis, we completed development of the inspection system of vibration by appling the most efficient detecting methods and verified the system's reliability through experiments.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 추계학술대회 논문집
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• pp.139-142
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• 1994

Ceramic filter using energy trapping pheonomenon is used bandpass filter at high frequency. In this paper, we analyzed theoretically ceramic filter characteristics of TS vibrational mode and also investigated experimentally it. The ceramic plate is PZT-4 poled in the thickness direction of Valpey Fisher Co. and electroded with two pairs. We analyzed the characteristics in appling to the all constant of ceramic and electrode material each other and vibrational mode. We also measured resonant frequency and bandpass width of the ceramic filter changing the thickness of ceramic plate and electrode spacing. Comparing of falter characteristics, theoretical value nearly corresponded with experimental value. So we saw that we can expect filter characteristics changing the thickness of ceramic plate and electrode spacing.

• 산업기술연구
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• 제10권
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• pp.21-32
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• 1990

Car body resonance often generates severe vibrational and noise problems in vehicle compartment. In this study, vibrational characteristics of 2-D vehicle compartment model is investigated and structural modification is carried out by numerical simulation to shift natural frequencies and to reduce stresses in resonance. To this end, ring models of the compartment are manufactured and analysed by FEA. The results are verified to be in good agreement with those of experimental modal testing. And the results of this study offer efficient strucural modification technique for vibration reduction of real cars.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.267-272
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• 2004

Vertical pump are widely used owing to the fact that they occupy small floor space. In this type of pumps, however, the vibrational problems are very important, since, in many cases, they have less stiffness in comparison with later pumps. This study presents a simple solution method for calculating the natural frequencies and modes of vertical pumps. In this study, a model of a vertical pump was developed and the nondimensional parameters for the vibrational characteristics of it were determined. Added mass was calculated for the effects of water and the transfer matrix method was used.

• 소음진동
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• 제9권5호
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• pp.928-935
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• 1999

Vertical pumps are widely used owing to the fact that they occupy small floor space. In this type of pumps, however, the vibrational problems are very important, since, in many cases, they have less stiffness in comparison with lateral pumps. This study presents a simple solution method for calculating the natural frequencies and modes of vertical pumps. In this study, a mode of a vertical pump was developed and the nondimensional parameters for the vibrational characteristics of it were determined. Added mass was calculated for the effects of water and the transfer matrix method was used.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 추계학술대회 논문집
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• pp.558-565
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• 1999

Rubber wheel-type AGT has two major kinds of bogie; one is the bogie type and the other and passenger loads. This paper deals with the statics analysis for two types of bogie frame subjected to combined external forces, as well as independent ones specified in UIC 515-4. Furthermore, the dynamics analysis is performed under vibrational loading conditions so as to compare dynamic characteristics, Numerical results by using commercial packages, Ⅰ-DEAS and NASTRAN show that maximum stresses do not exceed the yielding level of material used for both bogies. From an overall viewpoint of strength, the bogie type turns out to be superior to the steering type except the case of a lateral loading. It is also observed that the steering type shows a be stiffened. It is strongly anticipated that vibrational fatigue analysis should be carried out under realistic loading conditions closely matching to situations such as running surface and lateral clearances along the guideway.