• 한국공작기계학회논문집
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• 제15권6호
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• pp.97-104
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• 2006

The geometric configuration in the weight reduction designis very required to be started from the conceptual design with low cost, high performance and quality. In this point, a structural-topological shape concerned with conceptual design of structure is important. The method used in this paper combines three optimization techniques, where the shape and physical dimensions of the structure and material distribution are hierachically optimized, with the maximum rigidity of structure and lightweight. As the results, the technology of weight reduction design is considered in designs of aluminum control arm and inner panel of door.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 봄 학술발표회논문집
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• pp.187-194
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• 2000

Weight reduction for an automobile body is being sought for the fuel efficiency and the energy conservation. One way of the efforts is adopting Ultra Light Steel Auto Body (ULSAB) concept. The ULSAB concept can be used for the light weight of an automobile door with the tailor welded blank (TWB). A design process is defined for the TWB. The inner panel of door is designed by the TWB and optimization. The design starts from an existing component. At first, the hinge and inner reinforcements are removed. In the conceptual design stage, topology optimization is conducted to find the distribution of variable thicknesses. The number of parts and the welding lines are determined from the topology design. In the detailed design process, size optimization is carried out to find thickness while stiffness constraints are satisfied. The final parting lines are determined by shape optimization.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.576-581
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• 2002

The suspension is a structure that supports reading, writing head in information storage device. In order to develop the information storage device of high track density, it is necessary to study about the suspension. To satisfy operation condition of information storage device, the suspension shape is very important since it correlates to dynamic characteristics. Therefore, it is necessary to analyze the dynamic characteristics by using finite element analysis and to optimize the suspension of information storage device using size optimization and topology optimization. The suspension has various modes according to different kinds of frequency bandwidth. Sway mode and second torsion mode are especially critical among them. In this paper, we investigated method to improve bandwidth of sway and second torsion mode of HDD and ODD suspension by using size optimization and topology optimization.

• Structural Engineering and Mechanics
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• 제54권3호
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• pp.453-474
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• 2015

A hybrid approach of Particle Swarm Optimization (PSO) and Swallow Swarm Optimization algorithm (SSO) namely Hybrid Particle Swallow Swarm Optimization algorithm (HPSSO), is presented as a new variant of PSO algorithm for the highly nonlinear dynamic truss shape and size optimization with multiple natural frequency constraints. Experimentally validation of HPSSO on four benchmark trusses results in high performance in comparison to PSO variants and to those of different optimization techniques. The simulation results clearly show a good balance between global and local exploration abilities and consequently results in good optimum solution.

• 한국전산구조공학회논문집
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• 제25권1호
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• pp.73-80
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• 2012

대공간 구조물은 형태에 따라 구조물의 설계와 시공에 미치는 영향이 크기 때문에 초기 단계에서의 최적형태 설계가 중요하다. 그러나 기존의 대공간 구조물의 최적형태 설계는 구조엔지니어의 직관이나 경험을 바탕으로 수행되어 왔다. 따라서 본 연구에서는 대공간 트러스 구조물의 체계적인 최적형태 설계를 위해 위상최적화 기법과 Cellular Automata 모델을 이용한 통합프로세서를 제안하고자 한다. 먼저 위상최적화 기법을 이용하여 구조물의 초기 최적형상을 찾고, 다음 단계로 Cellular Automata 규칙에 의해 생성된 구조패턴을 적용하여 대공간 트러스 구조형태를 생성한다. 최종적으로 구조해석을 실시하고 크기최적화를 적용함으로써 설계조건을 만족하는 최적형태를 제안하고자 한다.

• 한국압력기기공학회 논문집
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• 제4권2호
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• pp.20-28
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• 2008

According to IAEA regulations, a transportation package of radioactive material should perform its intended function of containing the radioactive contents after the drop test, which is one of hypothetical accident conditions. Impact limiters attached to a transport cask absorb the most of impact energy. So, it is appreciated to determine properly the shape, size and material of impact limiters. A material data needed in this determination is a dynamic one. In this study, several materials considered as those of impact limiters were tested by a drop weight facility to acquire dynamic material characteristics data. Impact absorbing volume of the impact limiter was derived mathematically for each drop condition. A size optimization of impact limiter was conducted. The derived impact absorbing volumes were applied as constraints. These volumes should be less than critical volumes generated based on the dynamic material characteristics. The derived procedure to decide the shape of impact limiter can be useful at the preliminary design stage when the transportation package's outline is roughly determined and applied as input value.

• 한국생산제조학회지
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• 제22권1호
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• pp.63-69
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• 2013

In order to find the optimum design of structures that have characteristic natural frequency range, a numerical optimization method to solving eigenvalue problems is a widely used approach. However in the most cases, it is difficult to decide the accurate thickness and shape of structures that have allowable natural frequency in design constraints. Parallel analysis algorithm involving the feasible direction optimization method and Rayleigh-Ritz eigenvalue solving method is developed. The method is implemented by using finite element method. It calculates the optimal thickness and the thickness ratio of individual elements of the 2-D plane element through a parallel algorithm method which satisfy the design constraint of natural frequency. As a result this method of optimization for natural frequency by using finite element method can determine the optimal size or its ratio of geometrically complicated shape and large scale structure.

• 한국강구조학회 논문집
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• 제13권6호
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• pp.673-681
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• 2001

본 연구에서는 다설계 변수와 다제약 조건으로 구성된 단면, 형상 및 위상을 동시에 고려하는 구조물의 이산화 최적설계문제를 유전자알고리즘을 이용하여 체계화하였다. 본 연구에서는 유전자알고리즘의 적용방법을 초기화절차, 진화적 절차 그리고 유전적 절차로 구성하였다. 초기화절차에서는 한 세대의 개체 수만큼 염색체를 생성하고 진화적 절차는 구조해석의 결과를 분석하여 적합도를 계산하였다. 그리고 유전적 절차는 번식과 교배 및 돌연변이를 통하여 다음세대의 유전자를 생성하게된다. 이렇게 진화적 절차와 유전적 절차를 반복 수행하여 최적 해를 탐색한다. 본 연구에서는 설계자가 궁극적 목표로 하는 구조물의 응력 해석과 단면, 형상 및 위상최적설계를 동시에 수행할 수 있는 이산화 최적설계프로그램을 개발하고, 설계 예를 들어 비교 고찰하였다.

• Journal of Computational Design and Engineering
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• 제3권3호
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• pp.226-249
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• 2016

The symbiotic organisms search (SOS) algorithm is an effective metaheuristic developed in 2014, which mimics the symbiotic relationship among the living beings, such as mutualism, commensalism, and parasitism, to survive in the ecosystem. In this study, three modified versions of the SOS algorithm are proposed by introducing adaptive benefit factors in the basic SOS algorithm to improve its efficiency. The basic SOS algorithm only considers benefit factors, whereas the proposed variants of the SOS algorithm, consider effective combinations of adaptive benefit factors and benefit factors to study their competence to lay down a good balance between exploration and exploitation of the search space. The proposed algorithms are tested to suit its applications to the engineering structures subjected to dynamic excitation, which may lead to undesirable vibrations. Structure optimization problems become more challenging if the shape and size variables are taken into account along with the frequency. To check the feasibility and effectiveness of the proposed algorithms, six different planar and space trusses are subjected to experimental analysis. The results obtained using the proposed methods are compared with those obtained using other optimization methods well established in the literature. The results reveal that the adaptive SOS algorithm is more reliable and efficient than the basic SOS algorithm and other state-of-the-art algorithms.

• 동력기계공학회지
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• 제12권1호
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• pp.53-57
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• 2008

The automotive industry faces many competitive challenges including weight and cost reduction to meet need for higher fuel economy. It is a trend that a lot of parts have been currently changed to an aluminum alloy from steel materials. It is required more precise analysis for practical load because of complexities and varieties of vehicle structure. In this study, the shape optimization using a FEA is performed to determine the design of the knuckle. The size optimization is carried out to find thickness while the stiffness constraints are satisfied. A commercial optimization software MSC/NASTRAN is utilized for the structural analysis and the optimization processes.