• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.40 no.5
• /
• pp.513-523
• /
• 2016

The stress concentration factors and stress intensity factors for a simple beam and a cantilever are analyzed by using finite element method and phtoelasticity. Using the analyzed results, the estimated graphs on stress concentration factors and stress intensity factors are obtained. To analyze stress concentration factors of notch, the dimensionless notch length H(height of specimen)/h=1.1~2 and dimensionless gap space r(radius at the notch tip)/h=0.1~0.5 are used. where h=H-c and c is the notch length. As the notch gap length increases and the gap decreases, the stress concentration factors increase. Stress concentration factors of a simple beam are greater than those of a cantilever beam. However, actually, the maximum stress values under a load, a notch length and a gap occur more greatly in the cantilever beam than in the simple beam. To analyze stress intensity factors, the normalized crack length a(crack length)/H=0.2~0.5 is used. As the length of the crack increases, the normalized stress intensity factors increase. The stress intensity factors under a constant load and a crack length occur more greatly in the cantilever beam than in the simple beam.

• Journal of the Society of Naval Architects of Korea
• /
• v.33 no.3
• /
• pp.1-7
• /
• 1996

The stress concentration factor gives the significant effect the fatigue strength of welded joints. The model used herein is the type of the load carrying fillet welded cruciform joint with full or partial penetration. In order to obtain the stress concentration factor at the weld toe of fillet joint, the reasonable element size of the toe part is investigated and the stress analysis for the series models by FEM under tensile load is performed. On the basis of the calculation results, the estimated formulae for the stress concentration factor(Kt) at weld toe part of the fillet welded joint, which the effect of toe radius, flank angle and other parameters are taken into account, is derived.

• Proceedings of the Korean Society For Composite Materials Conference
• /
• 2003.04a
• /
• pp.83-86
• /
• 2003

동시경화조인트는 경화 시 복합재료로부터 흘러나오는 수지를 접착제로 사용하기 때문에 제조과정이 간편할 뿐 아니라 복합재료를 표면 처리할 필요가 없기 때문에 기존의 접착제에 의한 접합방법에 비해 장점을 지닌다. 최근 동시경화조인트에 관한 연구가 활발하게 진행되고 있으나 해석적인 방법을 통한 연구는 아직까지 미비하다. 실험적으로 연구된 결과를 보면 동시경화 조인트는 계면 모서리에서 파괴가 시작되어 계면을 따라 파괴가 진행된다. 그러므로 조인트의 계면 모서리에서의 응력집중계수에 관해 연구하는 것이 중요하다. 본 논문에서는 고유치 문제를 고려하여 복합재료와 강재료로 구성된 동시경화조인트의 계면 모서리에서 발생하는 응력 및 변위장을 결정하고, H-적분을 이용하여 응력집중계수를 구하는 방법을 제시하고자 한다.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.29 no.6
• /
• pp.491-498
• /
• 2016

Stress on plates may increase in the neighborhood the edges or the holes for rivets or bolts. Excessive stress concentration may lead to severe breakage of the plates. Thus, it is important to conduct optimization of arrangement of holes at the design stage. In this paper, accuracy of FEM analysis was examined for such stress concentration. By changing the hole size on a narrow plate, change of the stress concentration factor(K) was investigated. Additionally, the same experiment was conducted about series of multiple holes on plate to investigate interaction between the adjacent holes. Then, the FEM results were compared to the reference predictions respectively. Finally, a method by which simple stress concentrating situations can be optimized, will be suggested. This method was examined by FEM, and showed similar tendency with the expectation. Therefore, this method can be valuable when arranging the holes on a plate.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.9 no.3
• /
• pp.295-300
• /
• 1985

본 논문에서는 Dhir의 이론에 따라서 Mapping함수로 고차다항식을 사용하여 여러가지 하중상태에 따른 최적형상을 연구하고 Mapping함수에 포함되어 있는 계수가 응력집중 및 형상변화에 미치는 영향을 검토하며 광탄성 실험을 통하여 이론의 타당성 을 입증하고자 하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.28 no.2
• /
• pp.92-100
• /
• 2016

Reliability analysis of tripod support structure for offshore wind turbine was performed. Extreme distribution function of peak response due to wind and wave loads was estimated by applying peak over threshold(POT) method. Then, stress based limit state function was defined by using maximum stress of support structure which was obtained by multiplying beam stress and concentration factor. The reliability analysis result was compared when maximum stress was calculated from shell element. Reliability index was evaluated using first order reliability method(FORM).

• Journal of the Korean Geotechnical Society
• /
• v.18 no.5
• /
• pp.133-141
• /
• 2002

Isotropic rock and anisotropic rock have different tensile strength which has the greatest influence on rock failure. In this study, elastic modulus of anisotropic rock is obtained through uniaxial compression test, and tensile strength and tension failure behavior are analyzed through indirect tensile strength test. Stress concentration factor of a specimen at the center is obtained from anisotropic elastic modulus and strain by indirect tensile strength test. Theoretical solutions for tensile strength of isotropic and anisotropic rock are compared. Stress concentration factor of anisotropic rock is either higher or lower than isotropic rock depending on the inclination angle of bedding plane. The use of stress concentration factor of isotropic rock resulted in overestimation or underestimation of tensile strength.

• The Korean Journal of Applied Statistics
• /
• v.21 no.4
• /
• pp.581-588
• /
• 2008

The purpose of this study is to introduce a relative specialization index, the Nam-Oh-Hong Index(NOHI) and to investigate regional distribution of occupational specialization using the newly developed index. Compared with Location Quotient(LQ), the advantages of the index is that the NOHI enables comparison between inter-regional and intra-regional concentration of employment possible at the same time. The results of the specialization analyses show that Seoul is specialized in management, book-keeping and office related occupations, whereas Busan in machine and material related occupations.

• Journal of Advanced Marine Engineering and Technology
• /
• v.36 no.1
• /
• pp.85-93
• /
• 2012

In this study, the geometry of the weld is used to develop the process of fatigue life prediction. For the development of fatigue life prediction process, bending fatigue test of muffler is conducted to obtain M(Moment)-N(Fatigue life) diagram. Modeling the geometry of the weld which is failed is performed to conduct static load analysis and analysis results are used to calculate the stress concentration factor. The stress concentration factor is used to get the fatigue notch factor and this was based on the fatigue life prediction. As a result of the comparison of test values and predicted values, predicted values are verified.

• Journal of Ocean Engineering and Technology
• /
• v.4 no.2
• /
• pp.59-72
• /
• 1990

본 논문은 해양 구조물에 대한 확률적 기법을 이용한 스펙트럴 피로해석 방법에 대하여 기술하고 있다. 환경조건 특히 파도 및 관련된 해상상태, 파도 스펙트럼에 대하여 조사하였다. 각종 공식을 이용한 응력 집중계수와 유한요소법을 이용한 응력 집중계수 산출 방법 및 피로수명에 대한 그 영향에 대하여 연구하고, S-N선도의 선택과 해상상태의 간략화 문제등에 관해서도 다루었다. 마지막으로 스펙트럴 피로해석 기법을 응용한 실제 피로해석 사례 연구를 통하여 본 방법의 유용성을 입증하였다.