• 대한조선학회지
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• 제17권3호
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• pp.5-17
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• 1980

A basic procedure to design marine propellers by a curved lifting line theory was shown. By adapting discrete singularity method, it became possible to take into account of skew, rake and the contraction of slip stream in the early stage of preliminary design procedure. It is also shown that lifting line theory based on the discrete singularity method converges to a common solution obtained by induction factor method with a relatively small number of discrete elements. Lifting the blade geometry more accurately on the basis of hydrodynamic principles. A number of numerical results from lifting line calculation are presented for the purpose of comparison with the previous method, and with these results two sample designs are carried out, which are wake-adapted optimum and wake-adapted non-optimum propellers.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.112-119
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• 2002

In this paper, an Extended Finite Element Method is proposed by adding discontinuity and singularity enrichment functions to the standard FEM approximation. In this method, the singularity and the discontinuity of the crack are efficiently modeled by using initial regular mesh without refining mesh near the crack tip, so that it enables express the asymptotic stress field near crack tip and crack surface successfully. The developed method was verified by evaluating crack tip stress profile and stress intensity factor of mode Ⅰ/mode Ⅱ fracture problems and the results showed the effectiveness and robustness for fracture problem.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2003년도 추계학술대회 발표 논문집
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• pp.146-153
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• 2003

This paper deals with the stress singularity induced at the interface corner between the viscoelastic thin film and the rigid substrate subjected to the combined influence of temperature change and moisture absorption. A boundary element analysis is employed to investigate the behavior of interface stresses. The film is assumed to be thermorheologically simple. It is further assumed that moisture effects are analogous to thermal effects. Numerical results are presented for a given viscoelastic model, indicating the singular residual stresses induced during cooling down from the curing temperature, and how they can be altered by subsequent moisture absorption at room temperature.

• 반도체디스플레이기술학회지
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• 제9권3호
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• pp.35-39
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• 2010

Interfacial stress singularity induced in an analysis model consisting of the polymeric thin film and the elastic substrate has been investigated using the boundary element method. The interfacial singular stresses between the viscoelastic thin film and the elastic substrate subjected to a uniform moisture ingression are investigated for the case of a small interfacial edge crack. It is assumed that moisture effects are assumed to be analogous to thermal effects. Then, the overall stress intensity factor for the case of a small interfacial edge crack is computed. The numerical procedure does not permit calculation of the limiting case for which the edge crack length vanishes.

• 대한토목학회논문집
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• 제29권5A호
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• pp.457-465
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• 2009

본 연구는 균열선단에서 응력특이성을 갖는 탄성균열문제를 해석하기 위한 이동최소제곱 유한차분법을 제시한다. 응력특이성을 유발하는 균열선단 주변장을 모형화하기 위해 근사식에 선단주변함수를 내재적으로 도입하여 이동최소제곱 근사의 틀을 그대로 유지하면서 실제 미분계산을 거의 하지 않고 미분근사를 할 수 있는 이동최소제곱 Taylor 다항식 근사의 장점을 살렸다. 균열문제 정식화시 시간소모적인 적분과정이 필요한 약정식화 대신 해석영역에 배치된 절점에서 지배 미분방정식에 대한 차분식을 직접 구성하는 강정식화를 적용하여 계산 효율성을 향상시켰다. 균열문제 해석을 통해 내적확장된 이동최소제곱 유한차분법이 응력 특이성을 내포한 선단주변 변위장을 정확히 묘사할 수 있을 뿐만 아니라 응력확대계수를 정확히 계산 할 수 있음을 보였다.

• International Journal of Safety
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• 제2권1호
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• pp.17-22
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• 2003

In order to analyze general three dimensional cracks in an infinite body, the symmetric Galerkin boundary element method formulated by Li and Mear is used. A crack is modelled as distribution of displacement discontinuities, and the governing equation is formulated as singularity-reduced integral equations. With the proposed method several example problems for three dimensional cracks in an infinite solid, as well as their growth under fatigue, are solved and the accuracy and efficiency of the method are demonstrated.

• 전산구조공학
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• 제9권1호
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• pp.77-83
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• 1996

이 논문에서는 경계요소법을 사용하여 횡방향의 인장변형률을 받는 단일방향 graphite/epoxy 복합재료의 섬유와 기지의 공유면에 존재하는 모서리 균열에 대한 응력확대계수를 계산하였다. 그러한 균열은 복합재료의 자유경계면에서 발생하는 특이 응력들에 의해 야기될 수 있다. 응력확대계수의 크기는 균열길이가 작은 경우에는 균열길이에 따라 조금씩 증가되다가, 균열길이가 커지면 일정한 값에 이르게 된다.

• 대한기계학회논문집
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• 제15권1호
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• pp.179-189
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• 1991

본 연구에서는 특성근이 같은 같은 경우의 기본해 유도에서 사용하였던 상사 방법을 이용하여, 균열끝 부근의 응력장과 변위장을 나타내고자 한다. 위의 해석을 바탕으로 개발한 프로그램의 정도에 대하여 검증하고, 이 프로그램을 복합재료 내의 균열 문제에 응용하여 응력확대계수에 관한 자료를 계산하고, 그 유용성을 검토하고자 한다.

• 한국실내디자인학회논문집
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• 제18권5호
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• pp.164-174
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• 2009

Since the end of 19th century, The form and inner space for the religious ceremony; liturgical space of Catholic churches in Busan diocese have been changed as various styles by several outer and inner factors. The changing of historical, social, and religious environment, such as Opening Harbor, Japanese Occupation, Korean War & Rehabilitation Period, and Vatican II are generally regarded as main outer factors, and the locality that lay behind the flux of those events is considered as the main inner factor. The former has usually operated as a momentum for showing general trend of Catholic church, while the latter has made local singularity expressed as unusual style and somewhat modified liturgical space compared with Its contemporary churches. In the context, this paper attempt to analyze the transformation process of style and liturgical space of Catholic churches in Busan diocese focused on revealing local singularity with main five churches, Bumil Church, Samrangjin Church, Milyang Church, Jungang Church, and Dongrae Church, constructed between the end of 19th century and 1962.

• 대한조선학회논문집
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• 제35권4호
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• pp.46-54
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• 1998

노치의 기하학적 형상이 동적응력집중계수에 미치는 영향을 동적 광탄성 시험법을 이용하여 규명하였다. 동적 하중 장치로부터 발생하는 탄성파에 의하여 여러 종류의 노치의 기하학적 형상 주위에서 발생하는 동적응력장을 $10^6/sec$의 촬영 속도를 갖는 Cranz-Shardin형 카메라를 사용하여 12장면을 기록하였다. 다양한 노치 선단의 형상에 대한 동적응력특이지수를 간단한 모델링식으로 결정하는 방안을 제시하고, 여러 가지 노치의 기하학적 형상에 대응하여 발생하는 동적응력집중현상을 비교하는데 이용하였다. 동적 광탄성 시험법으로 얻어진 동적응력장을 면밀히 해석하여, 동적응력집중계수가 노치의 형상에 크게 의존함을 규명하였다.