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랜덤하중하의 피로균열진전 데이터를 이용한 △Keff 평가법의 정량적 평가
구자석(Ja-Suk Koo),송지호(Ji-Ho Song),강재윤(Jae-Youn Kang) 대한기계학회 2004 대한기계학회 춘추학술대회 Vol.2004 No.11
Methods for estimation of the effective stress intensity factor range (△Keff) are evaluated for narrow and wide band random loading crack growth test data of 2024-T351 aluminum alloy. Three methods of determining Kop, visual measurement, ASTM offset compliance method, and the neural network method proposed by Kang and Song, and three methods of estimating △Keff, conventional, the 2/PI0 and 2/PI methods proposed by Donald and Paris, are compared in a quantitative manner by using the results of fatigue crack growth life prediction under random loading. For all Kop determination methods discussed, the 2/PI0 and 2/PI methods of estimating △Keff provide better results than conventional method for narrow and wide band random loading data.
구자석(Jasuk Koo) 한국자동차공학회 2011 한국자동차공학회 학술대회 및 전시회 Vol.2011 No.11
Vibration fatigue analysis which is established by Dirlik at 1985, is widely used to developing automotive components or parts. For the vibration fatigue analysis, normal mode analysis and frequency response analysis precedes in order to obtain the system transfer function. The frequency request method in the frequency response analysis is very important factor to affect to the fatigue life of the components. In this study, we proposed the most effective frequency request method, which is requiring small number of frequency points, producing less output file size and giving reasonable results. For this study, we made a primitive analysis model and compared 18 frequency request methods to find out the best model. As a result, proposed method reduces output file size as 1/20 and gives 0.69 times of fatigue life compare to 1 Hz equally spaced frequency request method. This method could be utilized for the large sized models like as lamp system or automotive battery system, etc.
자동차용 고장력강 DP590의 인장 및 저되풀이수 피로물성 평가
구자석(Ja-Suk Koo),최재석(Jae-Seock Choi),전태룡(Tae-Ryong Jeon),허용학(Yong-Hak Huh),이해무(Hae-Moo Lee) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.5_2
Tensile and low cycle fatigue properties of high strength steel DP590 used for automotive chassis parts are evaluated. Test specimens are made of DP590 plate after painting and baking process. Load cell calibration, extensometer calibration and specimen alignment are performed to enhance the accuracy and precision. In addition, the guiding apparatus is made in order to prevent buckling when compression loading is present. When DP590 replaces SAPH370, the fatigue life of the lower control arm increases by 2 or 3 times.
구자석(J.S. Koo),이연규(Y.G Lee),최재석(J.S. Choi),주동국(D.G. Choo),신소영(S.Y.Shin),이태희(T.H. Lee) 한국자동차공학회 2006 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
An automated system for the structural analysis of chassis module are developed. The system can evaluate the deformation, strength and stiffness of the chassis module, when a heavy loads is applied at the wheel center or tire patch of the module. Part library, project model, and load files in the system are realized in the form of xml and are stored in a database for reuse. The system is actively being used in the vehicle developing process.
구자석(Jasuk Koo),박민수(Minsoo Park),이경민(Kyungmin Lee) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11
Keyword network analysis is the process of investigating network structures in the keyword data using graph theory. In this study, keyword network analysis was conducted on 862 papers presented at the spring conference of the Korean Society of Mechanical Engineers for the past 5 years. Network associations between authors were analyzed using author information. And using the paper title, the frequency of the research keywords and the degree of correlation between the keywords were analyzed. Five large research groups were identified. There are groups where many students gather around a professor, and groups where researchers conduct joint research. Noun and adjective keywords were extracted through morpheme analysis, and the frequency of simultaneous occurrence of a keyword pair in one paper title was confirmed. Keywords were clustered according to network modularity, with the top 5 clusters accounting for 70% of the total data. Through the two-mode keyword network analysis between the researcher and the title keyword, each research field and research networking were confirmed. According to the proposed keyword network analysis procedure, it is possible to identify trends in various research fields from the titles of the paper, identify key researchers, and identify researcher networks.
구자석(Jasuk Koo),박민수(Minsoo Park),이경민(Kyungmin Lee) 대한기계학회 2022 대한기계학회 춘추학술대회 Vol.2022 No.11
Keyword network analysis is the process of investigating network structures in the keyword data using graph theory. In this study, keyword network analysis was conducted on 862 papers presented at the spring conference of the Korean Society of Mechanical Engineers for the past 5 years. Network associations between authors were analyzed using author information. And using the paper title, the frequency of the research keywords and the degree of correlation between the keywords were analyzed. Five large research groups were identified. There are groups where many students gather around a professor, and groups where researchers conduct joint research. Noun and adjective keywords were extracted through morpheme analysis, and the frequency of simultaneous occurrence of a keyword pair in one paper title was confirmed. Keywords were clustered according to network modularity, with the top 5 clusters accounting for 70% of the total data. Through the two-mode keyword network analysis between the researcher and the title keyword, each research field and research networking were confirmed. According to the proposed keyword network analysis procedure, it is possible to identify trends in various research fields from the titles of the paper, identify key researchers, and identify researcher networks.
구자석(Jasuk Koo),최재석(Jaeseock Choi),전태룡(Taeryong Jeon) 한국자동차공학회 2005 한국자동차공학회 춘 추계 학술대회 논문집 Vol.2005 No.11_3
Vibration fatigue analysis of TPMS housing and antenna is performed in the frequency domain. It is well known that TPMS (Tire Pressure Measurement System) is a very important part in vehicle safety. In this study. we procedure mode analysis. modal frequency response analysis and vibration fatigue analysis. As a result, the TPMS housing and antenna is safe in the vibration environment, and the critical location is the curved position in the antenna.