http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
이억섭,김선용,홍성경,Lee, O.S.,Kim, S.Y.,Hong, S.K. 한국정밀공학회 1995 한국정밀공학회지 Vol.12 No.12
This investigation evaluates dynamic fracture characteristics of two alloy steels (STD-11 and STS-3) and a gray cast iron (GC-30). The dynamic fracture toughness of crack initiation and some of the dynamic fracturing characteristics were evaluated by using the instrumented Charpy impact testing procedures. It was found from experimental results for three kinds of materials that inertia force is directly proportional to impact velocity. The duration time of inertia force was found to be constant regardless of impact velocities in steel specimens.
이억섭(O S. Lee),최용길(Y K. Choi) 대한기계학회 2001 대한기계학회 춘추학술대회 Vol.2001 No.8
Fatal damages will be caused by a corrosion or crack defects in buried pipeline. The integrity must be assessed, when defects were detected and must be determined the maintenances or modifications. Thus, this paper was carries out experiment to understand the characteristics of fatigue crack propagation direction and fatigue life under the axial and mixed-mode loading condition pipeline with external surface groove. Result of each condition, when mode I controlled, the fatigue crack initiation points are concentrated at one point approximately and propagation directions are constant but in state of mode Ⅱcontrolled, crack initiation points are scattered.
이종재료의 접합면에 존재하는 균열선단의 응력장에 미치는 접합두께의 영향
이억섭(O.S.Lee),강희수(H.S.Kang) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.5_2
The effects of interface thickness on the stress field around the interface crack under dynamic loading are investigated using a finite element code(DYNA2D). It is found that the thinner thicknesses of an interface affect the stress field significantly. The maximum shear stress contour drawn in this study can be utilized in modeling analysis with aid of experimental counterpart.<br/>
[論文] Caustics방법에 의한 Polycarbonate의 J-적분값 결정에 관한 기초적 연구
이억섭(O. S. Lee),박기용(K. Y. Park) 한국자동차공학회 1990 오토저널 Vol.12 No.1
This study investigated a method for the determination of the J-integral for a tough glassy polymer such as polycarbonate plates by using the method of caustics. Comparing the values of J-integral determined by a numerical analysis and by the method of caustics, the method of caustics was found to be an effective experimental technique for the determination of the J-integral.<br/> The ratio between two J-integrals determined by the method of caustics and by finite element method converged into 1 within the limit oflow load. However, it was noticed that the greater the plastic zone at the crack tip was, the lower the J-integral obtained by the reflect method of caustics. This difference may be deduced from the damage at the crack tip such as craze appeared in the polycarbonate plate.<br/> It was confirmed that the ratio of Iongitudinal diameter(D_L) to transverse diameter (Dt) of caustics generally converged into 1 at the low load. The transition of the state of stress at the vicinity of a crack tip from plane strain to plane stress was deduced by noticing that the longitudinal diameter(D_I) grew faster than the transverse diameter(Dt) of caustics within the higher load range.
이억섭(O. S. LEE),나경찬(K. C. NAH) 한국자동차공학회 1995 한국자동차공학회 학술강연초록집 Vol.- No.-
자동차의 경량와, 안전화 대책으로 자동차 업체의 설계 및 성형 부문에서 재료특성 향상에 대하여 많은 연구가 이루어지고 이싿. 본 연구는 자유낙하 계장화 3점굽힘 하중장치를 이용하여 자동차에 시용되는 여러가지 재료들에 대한 동적균열 개시인성치 K_ld를 결정하는 방법론을 제시하기 위하여 수행한 실험적인 연구이며, 시험편의 형상과 시험방법의 표준화 등에 대한 기초적인 연구결과를 제시하였다. PMMA, 주철과 같은 취성재로 및 Polycarbooate 같은 연성재료에 대해서도 동적균열 개시인성치를 수정 샤르피시험편을 사용한여 비교적 간단하게 결정하는 방법론을 제시하였으며, 텁에 부착한 스트레인게이지의 스트레인값으로 산정한 동적균열 개시인성치나 시험편에 스트레인게어지를 부착하여 결정한 ㄱㅄ이 서로 잘 일치함을 밝혔다. 결론적으로 자유낙하에 의해서 등적균열 개시인성치를 결정할 때, 텁에 스트레인게이지를 부착하여 측정한 하중값을 사용하여 간단하게 K_ld를 결정할 수 있다.