• Nuclear Engineering and Technology
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• 제51권2호
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• pp.588-599
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• 2019

This research presents a structural design of high-level waste (HLW) container using ultra-high performance fiber reinforced concrete (UHP-FRC) material. The proposed design aims to overcome the drawbacks of the existing concrete containers which are heavy, difficult to fabricate, and expensive. In this study, the dry storage container (DSC) that commonly used at Canadian Nuclear facilities is selected to present the proposed design. The design has been performed such that the new UHP-FRC alternative has a structural stiffness equivalent to the existing steel-concrete-steel container under various loading scenarios. Size optimization technique is used with the aim of maximizing stiffness, and minimizing the cost while satisfying both the design stresses and construction requirements. Then, the integrity of the new design has been evaluated against accidental drop-impact events based on realistic drop scenarios. The optimization results showed: the stiffness of the UHP-FRC container (300 mm wall thick) is being in the range of 1.35-1.75 times the stiffness of existing DSC (550 mm wall thick). The use of UHP-FRC leads to decrease the container weight by more than 60%. The UHP-FRC container showed a significant enhancement in performance in comparison to the existing DSC design under considered accidental drop impact scenarios.

• 한국자동차공학회논문집
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• 제24권5호
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• pp.612-617
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• 2016

A motorcycle frame is a structure that endures the load and retains durability under various driving environments. A motorcycle has been developed with a diverse utility range, and its design has always been expanded to the newly created concept based on advanced engineering technologies. In this study, a compact motorcycle frame is considered to perform parametric studies that can enhance the stiffness of a frame with computational simulation. Finite element analysis is used to compare the deformation and stiffness of a base model and four case-models with three design-change-parameters. The parametric studies are analyzed to provide available methods that can be expected in the industrial fields of engineering design for a motorcycle frame.

• 콘크리트학회논문집
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• 제22권2호
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• pp.187-197
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• 2010

본 연구에서는 성능기반설계를 위한 기둥의 주철근비에 대하여 연구하였다. 일률적인 현행 설계기준과 달리, 다양한 기둥의 설계변수를 고려하여 기둥의 주철근을 정의하였다. 기둥의 최소철근비는 다음의 2 가지 사항을 고려하여 평가하였다; 1) 사용상태에서 콘크리트의 장기변형에 의한 철근의 조기항복 방지; 2) 내진설계시 기둥의 연성능력을 확보하기 위해 균열모멘트 이상의 극한휨강도 확보. 배근상태와 하중조건에 따른 기둥의 유효강성도 강도설계시 추가적으로 고려하였으며, 3 가지 사항을 고려한 주철근비 결정방법을 제안하였다. 제안된 방법은 설계예제에 적용되었다.

• Steel and Composite Structures
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• 제2권3호
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• pp.209-222
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• 2002

This paper describes the buckling phenomenon of a tubular truss with unsupported length through a full-scale test and presents a practical computational method for the design of the trusses allowing for the contribution of torsional stiffness against buckling, of which the effect has never been considered previously by others. The current practice for the design of a planar truss has largely been based on the linear elastic approach which cannot allow for the contribution of torsional stiffness and tension members in a structural system against buckling. The over-simplified analytical technique is unable to provide a realistic and an economical design to a structure. In this paper the stability theory is applied to the second-order analysis and design of the structural form, with detailed allowance for the instability and second-order effects in compliance with design code requirements. Finally, the paper demonstrates the application of the proposed method to the stability design of a commonly adopted truss system used in support of glass panels in which lateral bracing members are highly undesirable for economical and aesthetic reasons.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제34회 추계학술대회 개최
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• pp.166-171
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• 2001

In order to improve the efficiency of the design process and the quality of the resulting design for the application-based exclusive rolling element bearings, this study propose design methodologies by using a genetic-based combinatorial optimization. By the presence of discrete variables such as the number of rolling element (standard component) and by the engineering point of views, the design problem of the rolling element bearing can be characterized by the combinatorial optimization problem as a fully discrete optimization. A genetic algorithm is used to efficiently find a set of the optimum discrete design values from the pre-defined variable sets. To effectively deal with the design constraints and the multi-objective problem, a ranking penalty method is suggested for constructing a fitness function in the genetic-based combinatorial optimization. To evaluate the proposed design method, a robust performance analyzer of ball bearing based on quasi-static analysis is developed and the computer program is applied to some design problems, 1) maximize fatigue life, 2) maximize stiffness, 3) maximize fatigue life and stiffness, of a angular contact ball bearing. Optimum design results are demonstrate the effectiveness of the design method suggested in this study. It believed that the proposed methodologies can be effectively applied to other multi-objective discrete optimization problems.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.941-946
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• 2001

The objectives of this study are to investigate effective stiffness of Rectangular reinforced concrete bridge columns. It is reasonable to use yielding effective stiffness of columns in seismic bridge design, especially in case that plastic hinges form at the bridge columns. In this study, the material nonlinear analysis was conducted for 3, 240 column sections of which variables were the concrete compressive stress, the steel yielding stress, the longitudinal steel location parameter, the longitudinal steel ratio, the axial load level, and the diameter of section. Based on the analytical results, an effective stiffness including two variables(longitudinal steel ratio and axial load ratio) was proposed by regression analyses, and it is compared with test results and the proposed equation for yielding effective stiffness of circular bridge columns.

• 동력기계공학회지
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• 제16권2호
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• pp.11-16
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• 2012

In this paper, the authors formulate the sensitivity analysis algorithm for the natural frequency of a torsional shafting by expanding the transfer stiffness coefficient method. The basic concept of the present algorithm is based on the transfer of sensitivity stiffness coefficient, which is the derivative of stiffness coefficient with respect to design parameter, at every node from the first node to the last node in analytical model. The effectiveness of the present algorithm is confirmed by comparing the results of the sensitivity analysis and those of the reanalysis for the natural frequencies of a torsional shafting with a constant cross section. In numerical calculation, the design parameter is the diameter of the shaft element of the torsional shafting.

• 한국건설순환자원학회논문집
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• 제11권4호
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• pp.517-526
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• 2023

현장에서 재사용율이 높은 시스템 동바리를 대상으로 임의 설계와 과도한 가재새 보강을 지양하고자 성능평가를 근거로한 시스템 동바리의 수직재와 수평재의 연결부에 대한 연결 조건을 제시하고자 하였다. 이를 위하여 국내에 가설현장에 널리 사용되는 대표적인 연결재 유형인 디스크형과 포켓형을 대상을 하중방향(수직, 수평)과 가력방법(단조, 반복)에 대하여 회전강성을 평가하였다. 평가결과 현행 설계기준에서 연결재에 대하여 회전강성을 "0"으로 규정한 것과 달리 모든 시편에서 회전강성 값을 확인할 수 있었으며, 최대 회전강성은 디스크형 연결재를 사용하여 수직방향으로 반복 가력한 시편에서 회전강성값이 19.624 kNm/rad로 확인되었다.

• Steel and Composite Structures
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• 제19권2호
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• pp.349-368
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• 2015

This paper presents a new algorithm to find the optimal distribution of steel diagonal braces (SDB) using artificial bee colony optimization technique. The four different objective functions are employed based on the transfer function amplitude of; the top displacement, the top absolute acceleration, the base shear and the base moment. The stiffness parameter of SDB at each floor level is taken into account as design variables and the sum of the stiffness parameter of the SDB is accepted as an active constraint. An optimization algorithm based on the Artificial Bee Colony (ABC) algorithm is proposed to minimize the objective functions. The proposed ABC algorithm is applied to determine the optimal SDB distribution for planar buildings in order to rehabilitate existing planar steel buildings or to design new steel buildings. Three planar building models are chosen as numerical examples to demonstrate the validity of the proposed method. The optimal SDB designs are compared with a uniform SDB design that uniformly distributes the total stiffness across the structure. The results of the analysis clearly show that each optimal SDB placement, which is determined based on different performance objectives, performs well for its own design aim.

• 한국지진공학회논문집
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• 제11권2호
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• pp.105-113
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• 2007

본 연구에서는, 기존 철근 콘크리트 구조물에 적용된 직접 변위-기반 설계법을 적용 FRP 피복 보강된 성능개선 콘크리트 부재에 대한 정밀 비선형 휨 해석 및 내진성능설계의 구체적 알고리즘을 제시하였다. 비선형 휨 해석의 정밀 예측을 위하여 콘크리트 및 FRP 복합재료의 다축 구성관계를 고려하였으며, Chopra 등 (1999)이 제안한 직접 변위-기반 설계법(DDM)을 개선하여 철근콘크리트 기둥에 대한 성능개선을 위한 FRP 피복 보강을 위한 성능설계 알고리즘을 제시하였다. 제시된 직접 변위-기반 설계법은, 변위계수법과 비교하여, 비선형 거동이 큰 경우에도 목표 변위 성능 값에 대한 정확한 추정을 해준다. 이는 변위계수법이 항복 이전의 유효탄성계수를 사용하는 반면, 직접 변위-기반 설계법은 유효탄할선탄성계수를 고려하고 있어, 목표 변위에 따른 성능설계 평가에 있어서 보다 높은 연성비의 거동을 반영하고 있기 때문인 것으로 평가된다.