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베어링 마모시험을 이용한 진동신호의 통계적 파라미터 특성연구
전오성,황철호,윤병옥,은희준,Jun, Oh-Sung,Hwang, Cheol-Ho,Yoon, Byung-Ok,Eun, Hee-Joon 한국음향학회 1989 韓國音響學會誌 Vol.8 No.1
RMS, Kurtosis, Crest factor, Probability of exceedance와 Probability density function 등의 통계적 파라미터를 선정하여 베어링의 사용조건과 결함진전에 따른 변화특성을 조사하였다. 이를 위해 4볼 시험기에서 하중, 회전수 및 시간을 변화시키면서 실험하여 진동신호를 수집하고, 이를 A/D변환시킨 후 디지털 필터링하여 주파수 대역별 통계적 파라미터 값을 계산하였다. 실험결과, 하중이나 회전수와 같은 운전조건이 변화하는 경우 RMS의 값은 운전조건 변화에 따라 변하지만 Kurtosis 등의 통계적 파라미터들은 운전조건과 무관하게 steady한 결과를 나타내었다. 또한 통계적 파라미터와 시간과의 상관관계에 대한 실험으로부터 통계적 파라미터들을 결함의 진전 상태를 나타내는 파라미터로 사용할 수 있음을 확인하였으며, 따라서 파손방지를 위한 예측지표로서 이들 통계적 파라미터를 이용할 수 있을것으로 판단되었다. This paper is concerned with the characteristics on the statistical parameters of vibration signal from bearing with changing its operating conditions as well as the spreading of faults. The rms, Kurtosis, crest factor, probability of exceedance and probability density function have been chose as the statistical parameters. To characterize of each, vibration signals have been recorded from four ball tester at different loads, operation speeds and time. The values of the statistical parameters for each frequency band have been calculated after A/D conversion and digital filtering of the recorded signals. It has been found that unlike rms values the statistical parameters such as Kurtosis etc. are almost unchanging with the change of the operating conditions such as load and speed. This suggests that the statistical parameters may be used for determining the development of faults independent of the operating conditions. In fact, the statistical parameters deviate considerably from their respective normal values when the faults developed under load conditions in the samples, conforming the suggestion.
탄소섬유 열선의 스노우멜팅 데크 적용에 따른 열효율 및 열전달 해석 연구
김정근(Jeong-Keun Kim),김홍건(Hong-Gun Kim),은희준(Hee-Jun Eun),곽이구(Lee-Ku Kwac) 한국기계가공학회 2023 한국기계가공학회지 Vol.22 No.2
The development of floor decks is drawing attention, and an active movement to prevent slipping accidents due to freezing caused by snow or rain in the winter continues. This study was conducted to prevent slippage caused by freezing. As the heating wire becomes hot, it melts the ice on the floor, preventing slipping accidents during winter. Additionally, securing the safety of citizens and preventing fractures or bruises caused by sliding is possible. In particular, by comparing the temperature change between carbon fiber and iron chromium wire, carbon fiber shows approximately 22.2% higher thermal efficiency than iron-chromium wire, indicating the suitability of carbon fiber as a heating wire. ANSYS heat-transfer analysis was performed before product installation, and carbon-fiber heating wires were either placed in the center or arranged near the surface of the decks. Therefore, these carbon-fiber heating wires are installed on the deck to thaw the frozen parts, preventing slipping accidents.