• 한국항만학회지
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• 제7권1호
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• pp.5-12
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• 1993

In complex decision making such as ill-defined system, one of the main problem is how to treat ambiguous aspect of the decision making. According to the complexity and ambiguity of the objective systems, many types of evaluation attributes are necessary for the rational decision and the relationship among the attributes become complex and fuzzy. Fuzzy integral is very effective to evalute the complex system with interaction between attributes but how to save the evaluation efforts in the decision making process of grading the membership of the objects or alternative is the problem to be tackled. Because the more object there are to evaluate, the number of decisions to made increase exponentially. Therefore, this paper aimes to propose a new evaluation algorithm based on fuzzy integral which can save the evaluator's efforts in decision making process. The proposed algorithm is constructed as follows : First, compose the fuzzy measure by introducing AHP(Analytical Hierachy Process) & mutual interaction coefficient. Second, generate fuzzy measure value of monotone family set for calculating the fuzzy integral. The effectiveness of the proposed algorithm is investigated through the example and sensitivity of interaction coefficient is illustrated.

• Earthquakes and Structures
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• 제20권2호
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• pp.201-213
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• 2021

Contrast to the conventional jointed bridge design, integral abutment bridges (IABs) offer some marked advantages like reduced maintenance and enhanced service life of the structure due to elimination of joints in the deck and monolithic construction practices. However, the force transfer mechanism during seismic and thermal movements is a topic of interest owing to rigid connection between superstructure and substructure (piers and abutments). This study attempts to model an existing IAB by including the abutment backfill interaction and soil-foundation interaction effects using Winkler foundation assumption to determine its seismic response. Keeping in view the significance of abutment behavior in an IAB, the probability of damage to the abutment is evaluated using fragility function. Incremental Dynamic Analysis (IDA) approach is used in this regard, wherein, nonlinear time history analyses are conducted on the numerical model using a selected suite of ground motions with increasing intensities until damage to abutment. It is concluded from the fragility analysis results that for a MCE level earthquake in the location of integral bridge, the probability of complete damage to the abutment is minimal.

• 대한기계학회논문집
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• 제17권2호
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• pp.416-425
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• 1993

To investigate the characteristics of the merged jet arising from the interaction of two opposing curved wall jets over a circular cylinder in still air, mean velocity, Reynolds stresses, triple moments and integral length scale were measured using hot-wire anenometry. The turbulent kinetic energy and shear stress budget were evaluated using the measured data. The variations of the Reynolds stresses, the triple moment and integral length scale are severe in the interaction region. The pressure diffusion terms are found to be very large when compared the other terms in the interaction region. The distributions of the Reynolds stress and the triple moment in the similar region are found to be similar to those of conventional plane jets.

• 한국음향학회지
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• 제27권8호
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• pp.411-417
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• 2008

본 논문에서는 헬름홀쯔 적분 방정식에서 유도된 식을 이용하여 구조물의 표면 압력을 구조진동 성분에 대한 단순한 적분형태로 표현하여 음향방사 및 구조/음향 연성 문제를 수치적으로 푸는 방법에 대하여 다룬다. 이 식은 임의의 형상에 대하여 유도된 식으로 Rayleigh 식과 유사한 형태를 갖는다. 이 식을 이용하면 표면 압력을 구조물의 속도에 대한 단순 적분 형태로 나타낼 수 있기 때문에 경계요소법과 같이 연립방정식에 대한 행렬식을 풀 필요가 없다. 또한 헬름홀쯔 적분 방정식에 기반을 둔 다른 방법 들이 가지는 해의 유일성 문제도 갖지 않는 장점이 있다. 본 논문에서는 구형 셀에 대하여 수치해와 정해를 비교하여 제안한 방법의 타당성을 검증하였다.

• Journal of applied mathematics & informatics
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• 제8권1호
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• pp.59-69
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• 2001

The paper deals with the interaction between three Griffith cracks propagating under antiplane shear stress at the interface of two dissimilar infinite elastic half-spaces. The Fourier transform technique is used to reduce the elastodynamic problem to the solution of a set of integral equations which has been solved by using the finite Hilbert transform technique and Cooke’s result. The analytical expressions for the stress intensity factors at the crack tips are obtained. Numerical values of the interaction efect have been computed for and results show that interaction effects are either shielding or amplification depending on the location of each crack with respect to other and crack tip spacing. AMS Mathematics Subject Classification : 73M25.

• Nuclear Engineering and Technology
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• 제42권6호
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• pp.680-689
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• 2010

The crack-tip stress fields and fracture mechanics assessment parameters for a surface crack, such as the elastic stress intensity factor or the elastic-plastic J-integral, can be affected significantly by the adjacent cracks. Such a crack interaction effect due to multiple cracks can alter the fracture mechanics assessment parameters significantly. There are many factors to be considered, for instance the relative distance between adjacent cracks, the crack shape, and the loading condition, to quantify the crack interaction effect on the fracture mechanics assessment parameters. Thus, the current assessment codes on crack interaction effects (crack combination rules), including ASME Sec. XI, BS7910, British Energy R6 and API 579-1/ASME FFS-1, provide different rules for combining multiple surface cracks into a single surface crack. The present paper investigates crack interaction effects by evaluating the elastic stress intensity factor and the elastic-plastic J-integral of adjacent in-plane surface cracks in a plate through detailed 3-dimensional elastic and elastic-plastic finite element analyses. The effects on the fracture mechanics assessment parameters of the geometric parameters, the relative distance between two cracks, and the crack shape are investigated systematically. As for the loading condition, an axial tension is considered. Based on the finite element results, the acceptability of the crack combination rules provided in the existing guidance was investigated, and the relevant recommendations on a crack interaction for in-plane surface cracks are discussed. The present results can be used to develop more concrete guidance on crack interaction effects for crack shape characterization to evaluate the integrity of defective components.

• 대한화학회지
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• 제20권3호
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• pp.198-205
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• 1976

Parr의 Integral Hellmann-Feynman이론을 비대각꼴에 까지 일반화하여 의의를 갖도록 하였으며 그 특징을 논하였다. 그리하여 이 비대각꼴을 결정장론에 미치는 배치작용의 효과를 검토하는데 적용함으로서, 모든 차의 섭동 에너지를 하나의 묶음으로서 도입하였다. 그 결과 ${\Gamma}$, S 및 m로 특징지워지는 상태들에게, 파라미터화 할 수 있는 공통적인 동경적분이 존재하지 않음을 밝혔다. 그러나 만일 각 성분에 변형이 없고 동경성분에게 동등한 변형만이 있는 여기된 배치들의 작용만을 허락한다면, 이는 고전적인 결정장론에서 결정장 파라메터 10 Dq와 Condon-Slater 적분 $F^n$의 척도를 변경시키는 결과를 초래함을 알게 되었다.

• Bulletin of the Korean Chemical Society
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• 제22권9호
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• pp.945-947
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• 2001

The He-Xe interaction potential has been determined using a direct inversion of the experimentally reduced-viscosity collision integrals obtained from the corresponding states correlation. The potential is in a good agreement with the previously determined potential. The potential predicts viscosity and diffusion coefficients and they are found to be in a good agreement with experiment.

• 대한기계학회논문집
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• 제10권3호
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• pp.277-284
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• 1986

본 연구에서는 상호작용하는 난류경계층의 여러가지 상류상태를 이론적인 방 법으로 묘사하여, 상류상태를 정의하는 매개변수의 각각의 독립적인 영향을 살펴보았 다.

• Journal of Welding and Joining
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• 제14권1호
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• pp.38-46
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• 1996

High temperature low cycle fatigue crack growth behavior is investigated over a range of two temperatures and various frequencies in SUS 304 stainless steel. It is found that low frequency and temperature can enhance time-dependent crack growth. With high temperature, low frequency and long crack length, ${\Delta}J_c/{\Delta}J_ f$, the ratio of creep J integral range to fatigue J integral range is increased and time-dependent crack growth is accelerated. Interaction between ${\Delta}J_f$ and ${\Delta}J_c$ is occured at high frequency and low temparature and ${\Delta}J_c$, creep J integral range is fracture mechanical parameter on transition from cycle-dependent to time dependent crack growth in creep temperature region.