http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Wahyu Caesarendra,Prabuono Buyung Kosasih,Anh Kiet Tieu,Craig Alexander Simpson Moodie,최병근 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.8
There have been extensive studies on vibration based condition monitoring, prognosis of rotating element bearings; and reviews of the methods on how to identify bearing fault and predict the final failure reported widely in literature. The investigated bearings commonly discussed in the literatures were run in moderate and high rotating speed, and damages were artificially introduced e.g. with artificial crack or seeded defect. This paper deals with very low rotational-speed slewing bearing (1-4.5 rpm) without artificial fault. Two real vibration data were utilized, namely data collected from lab slewing bearing subject to accelerated life test and from a sheet metal company. Empirical mode decomposition (EMD) and ensemble empirical mode decomposition (EEMD) were applied in both lab slewing bearing data and real case data. Outer race fault (BPFO) and rolling element fault (BSF) frequencies of slewing bearing can be identified. However, these fault frequencies could not be identified using fast Fourier transform (FFT).
화력발전용 심리스 튜브 제조에 쓰이는 피어싱 플러그 공구강의 미끄럼 접촉 고온마모거동
최병영 ( Byung Young Choi ),구윤식 ( Yoon Sik Gu ),( Qiang Zhu ),( Hongtao Zhu ),( Kiet Tieu ) 대한금속재료학회(구 대한금속학회) 2015 대한금속·재료학회지 Vol.53 No.12
Sliding wear behaviors of piercing plug tool steels were investigated at 900 ℃ against low Cr ferritic steels containing 2 %Cr and 9 %Cr using a pin-on-disc CETR tribometer under condition of applied normal load of 20N in air. Formation of glaze layers consisting of porous Fe-oxides wear debris with rapid growth on worn surface of piercing plug tool and smooth surface of steels containing 2 % Cr resulted in decreased friction coefficient at an initial period followed by exhibited constant value of about 0.3 during the elevated temperature wear tests. It was found on the cross-section underneath the worn surface of the tool steels against the steels containing 2 %Cr that coarse ferrite with equiaxed grains by phase transformation and dynamic recrystallization was formed showing the decrease in hardness. On the other hand, formation of the glaze layers consisting of compact Cr-rich Fe-oxide wear debris on the worn surface of the tool steels at slow rates of materials transfer from the steels containing 9 %Cr resulted in the fluctuated friction coefficient ranging from about 1.0~1.1 to 0.4 followed by exhibited almost constant value of 0.2~0.3. It was also found on cross-section underneath worn surface of tool steels against the steels containing 9 %Cr that severely deformed microstructures by cyclic applied loading was formed below compact and continuous oxide layers. The results showed that the elevated temperature sliding wear of the piercing plug tool steels was dominated by oxidation, materials transfer and subsurface degradation such as dynamic recrystallization softening or severe deformation.