http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
인공신경회로망을 이용한 원공결함을 갖는 유한 폭 판재의 음향방출 음원특성과 파괴거동에 관한 연구
이장규(Zhang-Kyu Rhee),우창기(Chang-Ki Woo) 한국생산제조학회 2008 한국생산제조시스템학회 학술발표대회 논문집 Vol.2008 No.10
The objective of this study is to evaluate an acoustic emission (AE) source characterization and fracture behavior of the SM45C steel by using back-propagation neural network (BPN). In previous research Ref. [8] about k-nearest neighbor classifier (k-NNC) continuously, we used K-means clustering method as an unsupervised learning method for obtained multi-variate AE main data sets, such as AE counts, energy, amplitude, risetime, duration and counts to peak. Similarly, we applied k-NNC and BPN as a supervised learning method for obtained multi-variate AE working data sets. According to the error of convergence for determinant criterion Wilk's A, heuristic criteria D&B(Rij) and Tou values are discussed. As the results show that BPN produced some empty classes before or at the same time k-NNC detect fracture signals. And confirmed that could save trouble to AE signal processing if suitable error of convergence or acceptable encoding error gives to BPN.
음향방출 신호분류에 의한 SM45C 시효처리재의 인장변형 해석
이장규(Zhang-Kyu Rhee),우창기(Chang-Ki Woo),김용배(Yong-Bae Kim) 한국생산제조학회 2009 한국생산제조시스템학회 학술발표대회 논문집 Vol.2009 No.5
This study investigates tensile deformation of the stress aging heat-treated SM45C steel which are aging temperature at 250, 300℃, aging time at 1,3 hours, and applied load at 300, 400N conditions by using acoustic emission (AE). A signal processing technology used to evaluate an AE source characterization by 2 AE measurement systems, i.e., DiSP & PCI-2 AE hardware and AEwin™ software. In this study, most suitable aging condition appeared at 250℃, 3 hours and 300N. On the other hand, in case of 250℃, 3 hours, 400N and 300℃, 3 hours, 400N conditions, yield load decreased than other conditions according to the over-aging phenomena. Especially, In case of 300℃, 3 hours and 400N condition appeared AE energy in elastic limit fairly high than non-heat treatment specimen.
음향방출 신호를 이용한 SWS 490A 고장력강의 접합성 평가에 대한 실험적 연구
이장규(Zhang-Kyu Rhee),우창기(Chang-Ki Woo) 한국생산제조학회 2005 한국생산제조학회지 Vol.14 No.3
The object of this study is to investigate the effect of joinability by using acoustic emission(AE) signals and doing a pattern recognition for weld heat affected zone(HAZ) in tensile testing. This study was carried out an SWS 490A high tension steel for electric shielded metal arc welding(SMAW), CO₂ gas arc welding and TIG welding. And correspondingly, the root openings are 3, 4 and 2.8mm. The results of the tensile test of weld HAZ come out electric shield arc welding > CO₂ gas arc welding > TIG welding in case of single welding. It is believed that this is a phenomenon where difference of its root opening or base metal thickness. Also, the technique of AE is ideally suited to study variables which control time and stress dependent fracture or damage process in metallic materials.
K-최근접 이웃 분류기를 이용한 원공결함을 갖는 유한 폭 판재의 음향방출 음원특성과 파괴거동에 관한 연구
이장규(Zhang-Kyu Rhee),우창기(Chang-Ki Woo),오진수(Jin-Soo Oh) 한국생산제조학회 2008 한국생산제조시스템학회 학술발표대회 논문집 Vol.2008 No.5
The objective of this study is to evaluate an acoustic emission (AE) source characterization and fracture behavior of the SM45C steel by using k-nearest neighbor (KNN) classifier. In previous research continuously, simple tension and AE tests were conducted against the 5 kind of circular hole defect coupons. Also, for this, we used K-means clustering as an unsupervised learning method for obtained multivariate AE main data sets, such as AE counts, energy, amplitude, risetime, duration and counts to peak. And we applied KNN classifier as a supervised learning pattern recognition algorithm for obtained multivariate AE working data sets. Through the classified results, i.e., determinant criterion (Wilk) and heuristic criteria (Rij & Tou), of the effectiveness of the proposed method is discussed.
맞대기 용접 이음재 연장시험에서 발생한 음향방출 신호의 웨이블릿 변환과 응용
이장규(Zhang-Kyu Rhee),윤종희(Joung-Hwi Yoon),우창기(Chang-Ki Woo),박성완(Sung-Oan Park),김봉각(Bong-Gag Kim),조대희(Dae-Hee Jo) 한국생산제조학회 2005 한국생산제조시스템학회 학술발표대회 논문집 Vol.2005 No.5
This study was carried out fusion-welded butt joints in SWS 490A high strength steel subjected to tensile test that load-deflection curve. The windowed or short-time Fourier transform (WFT or SIFT) makes possible for the analysis of non-stationary or transient signals into a joint time-frequency domain and the wavelet transform (WT) is used to decompose the acoustic emission (AE) signal into various discrete series of sequences over different frequency bands. In this paper, for acoustic emission signal analysis to use a continuous wavelet transform, in which the Gabor wavelet base on a Gaussian window function is applied to the time-frequency domain. A wavelet transform is demonstrated and the plots are very powerful in the recognition of the acoustic emission features. As a result, the technique of acoustic emission is ideally suited to study variables which control time and stress dependent fracture or damage process in metallic materials.
음향방출 신호를 이용한 SWS 490A 고장력강의 접합성 평가에 대한 실험적 연구
이장규(Zhang-Kyu Rhee),우창기(Chang-Ki Woo),윤종희(Joung-Hwi Yoon),조진호(Jin-Ho Cho),조대희(Dae-Hee Cho),박성완(Sung-Oan Park),김봉각(Bong-Gag Kim),구영덕(Young-Duk Koo) 한국생산제조학회 2004 한국생산제조시스템학회 학술발표대회 논문집 Vol.2004 No.10
The object of this study is to investigate the effect of joinability by using acoustic emission (AE) signals and doing a pattern recognition for weld heat affected zone (HAZ) in tensile testing. This study was carried out an SWS 490A high tension steel for electric shielded metal arc welding (SMAW), C₂ gas arc welding and TIG welding. And correspondingly, the root openings are 3, 4 and 2.8㎜. The results of the tensile test of weld HAZ come out electric shield arc welding > CO₂ gas arc welding > TIG welding in case of single welding. It is believed that this is a phenomenon where difference of its root opening or base metal thickness. Also, the technique of AE is ideally suited to study variables which control time and stress dependent fracture or damage process in metallic materials.
인공신경회로망을 이용한 원공결함을 갖는 유한 폭 판재의 음향방출 음원특성과 파괴거동에 관한 연구
이장규(Zhang-Kyu Rhee),우창기(Chang-Ki Woo) 한국생산제조학회 2009 한국생산제조학회지 Vol.18 No.2
The objective of this study is to evaluate an acoustic emission (AE) source characterization and fracture behavior of the SM45C steel by using back-propagation neural network (BPN). In previous research Ref. [8] about k-nearest neighbor classifier (k-NNC) continuity, we used K-means clustering method as an unsupervised learning method for obtaining multi-variate AE main data sets, such as AE counts, energy, amplitude, risetime, duration and counts to peak. Similarly, we applied k-NNC and BPN as a supervised learning method for obtaining multi-variate AE working data sets. According to the error of convergence for determinant criterion Wilk's λ, heuristic criteria D&B(Rij) and Tou values are discussed. As a result, in k-NNC before fracture signal is detected or when fracture signal is detected, showed that produce some empty classes in BPN. And we confirmed that could save trouble in AE signal processing if suitable error of convergence or acceptable encoding error give to BPN.
음향방출 신호분류에 의한 SM45C 고주파 열처리 강의 인장변형 해석
이장규(Zhang-Kyu Rhee),조규태(Kyu-Tae Cho),우창기(Chang-Ki Woo) 한국생산제조학회 2009 한국생산제조시스템학회 학술발표대회 논문집 Vol.2009 No.10
This study is deal with the high frequency induction hardening SM45C steel at 850℃, 120㎑ & 50㎾. And giving change to tempering temperature at 150℃, 300℃ & 450℃, tempering time at 0.5, 1.0 & 1.5 hours. The high frequency induction hardening specimen tempered at 150℃, did not appear any tempering effect of test pieces. A brittle fracture occurred at rounded area of tensile specimen, it showed that AE amplitude was relatively low at 45-60㏈. For the specimen which was tempered at 300 ℃, slip and fracture occurred at the hole area of tensile specimen. As it passes the yield point, the number of AE counts and energy value increased intermittently and amplitude was between 70~85㏈. In addition, after the maximum tensile load, it showed relatively high amplitude and energy distribution. Amplitude was between 45~70㏈. For the specimen which was tempered at 450℃, brittle fracture occurred as if it is torn in the direction of 45° on parallel area over the both sides of tensile specimen, which led to several peak value to be appeared in the number of AE counts. It was found that amplitude was relatively low and the energy value was high.