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이춘열,배준우,YOUNG SUCK CHAI 한국원자력학회 2005 Nuclear Engineering and Technology Vol.37 No.2
Fretting, which is a special type of wear, is defined as small amplitude relative motion along the contacting interface between two materials. The structural integrity of steam generators in nuclear power plants is very much dependent upon the fretting wear characteristics of Inconel 690 U-tubes. In this study, a finite element model that can simulate fretting wear on the secondary side of the steam generator was developed and used for a quantitative investigation of the fretting wear phenomenon. Finite element modeling of elastic contact wear problems was performed to demonstrate the feasibility of applying the finite element method to fretting wear problems. The elastic beam problem, with existing solutions, is treated as a numerical example. By introducing a control parameter s, which scaled up the wear constant and scaled down the cycle numbers, the algorithm was shown to greatly reduce the time required for the analysis. The work rate model was adopted in the wear model. In the three-dimensional finite element analysis, a quarterly symmetric model was used to simulate cross tubes contacting at right angles. The wear constant of Inconel 690 in the work rate model was taken as K=26.7 10-15 Pa-1 from experimental data obtained using a fretting wear test rig with a piezoelectric actuator. The analyses revealed donut-shaped wear along the contacting boundary, which is a typical feature of fretting wear.
이춘열 국민대학교 정보기술연구소 2004 정보기술연구 Vol.10 No.-
This study expands data quality management to include data transformation processes as well as data. Further, an information structure graph is applied to represent data transformations processes. An information structure graph is based on a relational database scheme. Thus, data transformation processes may be stored in a relational database. This kind of integration of data transformation metadata with technical metadata eases evaluation of database qualities and their causes.
접촉문제에서의 변분부등식의 유한요소해석과 A Priori 오차계산법
이춘열,Lee, Choon-Yeol 대한기계학회 1996 大韓機械學會論文集A Vol.20 No.9
Governing equations infrictional contact problems are introduced using variational inequality formulations which are regularized to overcome the diffculties of non-differentiability of the friction functional. Also finite element approximations and a priori error estimations are derived based on those formulations. Numerical simulations are performed illustrating the theoretical results.
기둥형 로드셀 감지부의 설계변수에 따른 비선형 거동해석
이춘열,강대임,Lee, Chun-Yeol,Gang, Dae-Im 대한기계학회 2000 大韓機械學會論文集A Vol.24 No.6
Recently, force measurement systems are commonly used in many industrial fields and the precision of the measurement system is getting more important as the industry needs more precise tools and in struments to make high quality products. However, a high precision force measurement system is hard to make unless we know precisely the causes, quality and quantity of measurement errors in advance. In this work, many possible mechanical causes of measurement errors are reviewed including ratio of length to diameter of sensing part, radius of contact area, radius of bearing part, ratio of material properties and change of boundary conditions. Also, the measurement errors are analyzed by nonlinear finite element method and the nonlinear behavior of the errors are investigated. The results can be used to design force measurement systems and expected to be very useful especially for compact type load cells.