1. 제 목 : Asymptotic Stress Analysis of Woven Fabric Composites





2. 연 사 : Dr. Sangwook Sihn


Research Engineer, University of Dayton Research Institute





3. 일 시 : 2002년 12월 9일 (월) 16:00 - 17:00





4. 장 소 : 서울대 신공학관(301동) 1112호





5. 내 용 :


A numerical method based on 3-D B-spline finite element was used for a detailed stress analysis in the vicinity of the crimping regions to calculate the interlaminar stresses at the yarn interfaces with and without inter-yarn delamination. A penalty function approach along with the contact surface characteristic function was used to obtain the full-field numerical solution for the frictionless contact problem between the delaminated yarn surfaces. The fiber yarns were modeled as homogeneous unidirectional materials with continuously varying orientation. The yarn interfaces at the yarn crossover locations contain materials discontinuity due to three materials juncture. The homogenized yarn level model, therefore, results in singular stress behavior in these regions, which requires asymptotic analysis in the singular regions to alleviate known difficulties of the numerical analysis near the singularities, such as directional non-uniqueness of singular stress functions. In the present study, asymptotically converged solutions in the vicinity of the yarn intersection have been demonstrated for the first time for the woven fabric composites. Coefficients of the asymptotic expansion were obtained by comparing the full-field numerical solution with the multi-term asymptotic


expansions in the vicinity of the singular point.





6. 약력 및 수상 경력 :





1990 B.S. Naval Architecture, Seoul National University


1992 M.S. Mechanical Engineering, Stanford University


1997 Ph. D, Mechanical Engineering, Stanford University


1997-1999 Postdoctoral Research Affiliate, Stanford University


1996-present Research Engineer at Wright-Patterson Air Force Research Lab.





7. 문 의 : 기계항공공학부 김 승 조 교수 (☏ 880-7388)