• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.4
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• pp.133-141
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• 2012

This study investigates structural and fatigue analyses of bike brake. Maximum equivalent stress of the model of mountain bike is 4 times as much as the model of general bike at static analysis. In cases of mountain and general bikes, maximum damage frequency at load of 'SAE bracket history' with the severest change of load becomes as much as 16 times than the most stable load of 'Sample history' among the nonuniform fatigue loads. In case of mountain bike, the possibility of maximum damage becomes 3% at the load of 'Sample history' with the average stress of 0 to $-3{\times}10^4$MPa and the amplitude stress of 0 to $10^4$MPa. In case of general bike, the possibility of maximum damage becomes 3% at the load of 'Sample history' with the average stress of 0 to $-0.8{\times}10^4$MPa and the amplitude stress of 0 to $0.2{\times}10^4$MPa. This stress state can be shown as 5 to 6 times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The analysis result of this study can be effectively utilized for the safe design of bike brake.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.4
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• pp.493-498
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• 2006

In this paper, we propose a blood pressure measurement method using ANFIS. Usually, the maximum and minimum blood pressures are calculated by Maximum Amplitude Algorithm(MAA) method. However, the MAA method has some drawbacks to measure exact blood pressure since it uses a fixed ratio to set the measuring points for everyone without considering individual's special conditions. To solve this problem, the pressures measured by the MMA are trained by ANFIS having self-learning ability. From various experiments, we confirm that the proposed method shows better performance than conventional method.

• Journal of Biomedical Engineering Research
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• v.16 no.2
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• pp.217-222
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• 1995

We propose some applications of image processing techniques to extract quantitative measurements by using a camera system developed in Korea university and Catholic Medical School. From now on the system will be called as KCMOTION. The purpose of this study is to provide basic kinematic and kinetic data for the analysis of human movements and to find the clinical usefulness and reliability of the proposed motion analysis system. Two tests, sit-to-stand (STS) movements and pendulum test, are conducted by the system. The aims of the tests are to identify variability and reliability of KCMOTION to give some quantitative comparisons to the other systems. The result of STS movement are compared to the LOCUS IIID motion analyzer by the ratio of maximum flexion movement per body weight to the actual maximum flexion extension torque per body weight. That result in 29 % and 33 % for hip and knee joint, respectively in KCMOTION and 27 % and 30 % in LOCUS IIID System. The results of the pendulum movements are compared to that of using Cybex and Electrogoniometer with relaxation index, amplitude ratio, swing number and swing time. The results of relaxation index and amplitude ratio of the KCMOTION are between those of the Cybex and Electrogoniometer. We also observed that the KCMOTION detect more natural movement, from the results of swing number and time.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.4
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• pp.613-618
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• 2012

The Ultrasonic metal welding is used in the solid-phase welding method at room temperature or low temperature state. In welding process, the high frequency vibration energy is delivered to the welding part under the constant pressure for welding. In this study, we aimed to design and manufacture a 40,000 Hz band horn through finite element analysis. By performing modal analysis and harmonic response analysis, the modal analysis result is that the horn frequency was 39,599Hz and the harmonic response result that the horn frequency was 39,533Hz. These results were similar. In order to observe the designed horn's performance, about 4,000 voltage data was obtained from a light sensor and was analyzed by FFT analysis using Origin Tool. The result RMS amplitude was approximately $8.5{\mu}m$ at 40,000Hz, and maximum amplitude was $12.3{\mu}m$. Using this manufactured horn along with an ultrasonic metal welder and tension tester, the weldability of Cu sheets was evaluated. The maximum tensile force was 66.53 N in the welding condition of 2.0 bar pressure, 60% amplitude, and 0.32 s welding time. In excessive welding conditions, it was revealed that weldability is influenced negatively.

• Journal of Power System Engineering
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• v.8 no.4
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• pp.11-16
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• 2004

In this study, to investigate the effects of omitting low-amplitude cycles from a flight-simulation loading, crack growth tests were conducted on 2124-T851 aluminum alloy specimens. Three test spectra were generated by omitting small load ranges as counted by the rain-flow count method. The crack growth test results were compared with the data obtained from the flight-simulation loading. The experimental results show that the ranges equal to or smaller than 5% of the maximum load do not contribute to crack growth behavior because these are below the initial stress intensity factor range. Omitting these from the flight-simulation loading, test time can be reduced by 54%. However, in the case of omitting the load ranges below 15% of the maximum load, crack growth rates decreased, and crack growth curve deviated from the crack growth data under the flight-simulation loading because loading cycles above fatigue fracture toughness were omitted.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.4
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• pp.68-74
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• 1999

Ths paper does acoustic detection of partial discharge using acoustic sensor in polymer. Time sequential rreasurement of acoustic emission characteristic obtained acoustic sensor deal with statistics process. and 5 characteristic quantities were introduced into this paper. Resulting fann analysis of $\psi$-AEA-n pattern (phase-acoustic emission amplitude-pulse number) and AE quantities ,it can know useful statistics quantities that AE average inception amplitude TEX>$(\overline{AEA_{inc}})$ and AE average maximum amplitude TEX>$(\overline{AEA_{max}})$ make diagnosis of the middle stage of deterioration, AE pulse number and AE average maximum phase $(\overline{\theta{max}})$ make diagnosis of the last stage of deterioration. it obtained that these AE quantities are useful for dias,mosis deterioration form experiment results.esults.

• Journal of KSNVE
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• v.3 no.1
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• pp.29-37
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• 1993

This study is concerned about the impact type damper for effectively restraining the high vibration amplitude in the resonance regions. The theoretical analysis is based on the assumption that the impacts occur twice per cycle at an equal time interval. Simple but reasonable approximations have been derived for the optimum collision clearance and maximum amplitude ratio. Using the impact dampers which is rigidly attached to the primary vibration system, we have experimented for mass ratios and restitution coefficients. The experimental results are in good agreement with theoretical results.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.4
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• pp.339-345
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• 1992

Estimates of maximum amplitudes of conductor galloping are needed in order to determine appropriate phase-to-phase clearances on the overhead lines. One approach to obtaining these estimates is through the use of mathematical models of conductor galloping. Unfortunately, the models that consider both vertical conductor motion (Den Hartog type) and torsional conductor motion are often too complex for practical use. However, the estimates of maximum amplitude obtained from galloping models that assume only vertical (Den Hartog type) conductor motion tend to be too conservative. This paper presents the DF method to obtain the estimates of the amplitude and the frequency of galloping limit cycle, along with the wind pressure at which they occur, from a nonlinear dynamic model that considers both Den Hartog type and torsional conductor motion. From these results, the useful data for the line design guide and further insight into the mechanism of the conductor galloping are obtained.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.11 no.5
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• pp.68-75
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• 2012

This study aims at the structural analysis of vibration and fatigue according to the tie rod configuration. The maximum displacement amplitude is happened at 156Hz by harmonic vibration analysis, this tie rod model can be broken as the weakest state. Among the cases of nonuniform fatigue loads, 'SAE bracket history' with the severest change of load becomes most unstable but 'Sine wave' becomes most stable. In case of 'Sine wave' with the average stress of 0MPa and the amplitude stress of 570MPa, the possibility of maximum damage becomes 70%. This stress state can be shown with 140 times more than the damage possibility of 'SAE bracket history' or 'SAE transmission'. The structural result of this study can be effectively utilized with the design on tie rod by investigating prevention and durability against its damage.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.943-947
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• 2008

Dynamic response characteristics of a beam undergoing impulsive force are investigated using the wavelet transform method in this study. When an impulse is applied to an arbitrary position of a beam, it will generate a structural deformation wave. The characteristics of the wave are changing in the domain of time and space. The maximum amplitude of each natural frequency mode and the time to reach the maximum amplitude are obtained in this study. The effects of the location of impulse on the variations of the dynamic characteristics is also investigated.