• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2006년도 정기 학술대회 논문집
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• pp.805-812
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• 2006

An optimization formulation is proposed to minimize sound pressures in a two-dimensional cavity by controlling the attachment area of unconstrained damping materials. For the analysis of structural-acoustic systems, a hybrid approach that uses finite elements for structures and boundary elements for cavity is adopted. Four-parameter fractional derivative model is used to accurately represent dynamic characteristics oJ the viscoelastic materials with frequency and temperature. Optimal layouts of the unconstrained damping layer on structural wall of cavity are identified according to temperatures and the amount of damping material by using a numerical search algorithm.

• 한국지진공학회논문집
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• 제21권2호
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• pp.105-114
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• 2017

Nonlinear analysis for seismic performance evaluation of existing building usually takes 4~5 times more than linear analysis based on KBC code. To obtain accurate results from the nonlinear analysis, there are a lot of things to be considered for nonlinear analysis modeling. For example, reinforcing layout, applied load and seismic details affect behavior of structural members for the existing building. Engineer-oriented computerized system was developed for engineers to evaluate effective seismic performance of existing buildings with abiding by seismic design principles. Using the engineer-oriented program, seismic performance evaluation of reinforced concrete building was performed. Nonlinear hinge properties were applied with real time multiple consideration such as section layout, section analysis result, applied load and performance levels. As a result, the building was evaluated to satisfy LS(Life Safety) performance level. A comparison between engineer-oriented and program-oriented results is presented to show how important the role of structural engineer is for seismic performance evaluation of existing buildings.

• 복식
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• 제59권7호
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• pp.100-113
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• 2009

The purpose of this study is to investigate how VMD structural elements affect fashion brand attitude and intention of store revisiting. For the research, we surveyed 200 females in their 20's and 30's, who are target consumers of SPA brands from April 10th to 15th in 2009. With SPSS 12.0 program, the data was analysed by frequency analysis, reliability analysis, factor analysis and multiple regression analysis. The results are as follows: First, regarding to the results of factor analysis, VMD structural elements were divided into the space layout and information factor, display and aesthetic factor, and store atmosphere factor. Second, intention of store revisiting was statically affected by fashion brand attitude and VMD structural elements, especially space layout and information factor. Third, we found differences in the path effects of VMD structural elements - brand attitude - store revisiting according to the familiarity of SPA stores. The results revealed that VMD structural elements are important marketing strategic tools affecting consumer's preference and store behavior on fashion brands.

• International Journal of Aeronautical and Space Sciences
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• 제16권3호
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• pp.370-379
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• 2015

Handling constantly evolving configurations of aircraft can be inefficient and frustrating to design engineers, especially true in the early design phase when many design parameters are changeable throughout trade-off studies. In this paper, a physics-based design framework using parametric modeling is introduced, which is designated as DIAMOND/AIRCRAFT and developed for structural design of transport aircraft in the conceptual and preliminary design phase. DIAMOND/AIRCRAFT can relieve the burden of labor-intensive and time-consuming configuration changes with powerful parametric modeling techniques that can manipulate ever-changing geometric parameters for external layout of design alternatives. Furthermore, the design framework is capable of generating FE model in an automated fashion based on the internal structural layout, basically a set of design parameters describing the structural members in terms of their physical properties such as location, spacing and quantities. The design framework performs structural sizing using the FE model including both primary and secondary structural levels. This physics-based approach improves the accuracy of weight estimation significantly as compared with empirical methods. In this study, combining a physics-based model with parameter modeling techniques delivers a high-fidelity design framework, remarkably expediting otherwise slow and tedious design process of the early design phase.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
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• pp.119-126
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• 2004

A continuum-based design sensitivity analysis and topology optimization methods are developed for power flow analysis. Efficient adjoint sensitivity analysis method is employed and further extended to topology optimization problems. Young's moduli of all the finite elements are selected as design variables and parameterized using a bulk material density function. The objective function and constraint are an energy compliance of the system and an allowable volume fraction, respectively. A gradient-based optimization, the modified method of feasible direction, is used to obtain the optimal material layout. Through several numerical examples, we notice that the developed design sensitivity analysis method is very accurate and efficient compared with the finite difference sensitivity. Also, the topology optimization method provides physically meaningful results. The developed is design sensitivity analysis method is very useful to systematically predict the impact on the design variations. Furthermore, the topology optimization method can be utilized in the layout design of structural systems.

• 한국구조물진단유지관리공학회 논문집
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• 제21권2호
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• pp.95-102
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• 2017

본 연구는 철근상세(대각선 및 수평 철근상세)가 실규모 연결보의 구조성능에 미치는 영향을 평가하기 위하여 실시되었다. 연결보의 시공성 및 경제성을 향상시키기 위하여 고강도 철근(SD500 및 SD600)을 사용하였다. 반복하중이 작용하는 동안 연결보의 순경간(양쪽 전 단벽 사이의 간격)을 유지하기 위하여 강체 프레임 및 링크조인트를 설치하였다. 실험결과 대각선 철근상세을 적용한 연결보가 수평 철근상세 연결보에 비해 높은 연성을 나타내었다. AC1318-14 기준은 대각선 철근상세의 연결보 설계에는 적용이 가능할 것으로 판단되나, 수평 철근상세 연결보의 최대내력은 과대평가하는 것으로 나타났다. ASCE 41-13에서 제시된 연결보의 유효강성은 대각선 및 수평 철근상세를 적용한 연결보의 실험결과를 과대평가하고 있는 것으로 판단된다.

• 한국건축시공학회지
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• 제22권6호
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• pp.689-700
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• 2022

건축물 골조공사에서 먹매김 작업은 건축물 구조부재 요소를 정확한 위치에 시공하기 위해 높은 정밀도가 요구되나, 현재 인력에 의해서 진행되어 작업자의 숙련도에 따라 먹 위치 정확도 및 정밀도가 저하되고, 정보손실 및 오류 발생에 따른 생산성 저하 문제점을 갖는다. 이를 해결하기 위해 전반적인 먹매김 공정의 자동화 및 정보화 기술 도입이 요구되며, 건설로봇을 활용한 먹매김 자동화는 효과적인 수단이 될 수 있다. 이에 본 연구에서는 건축물 골조공사의 먹매김 시공자동화 로봇의 프로토타입을 개발하고 기초성능을 평가하였다. 개발된 로봇은 크게 주행부, 마킹부, 센싱부, 제어부로 구성되었으며, 골조공사 환경을 고려하여 다양한 주행방식과 마킹부 이동 및 회전이 가능하도록 설계되었다. 주행 및 마킹 성능 실험 결과, 주행거리 오차 및 마킹 품질측면에서는 만족할 만한 성능을 보였으나, 일부 주행방식과 마킹 정밀도 측면에서의 개선 필요성이 확인되었다. 본 연구결과를 토대로 개발 장비의 지속적인 개선 및 성능 보완, 전체 먹매김 공정의 자동화 시스템 구축을 진행하고자 한다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제11권2호
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• pp.809-818
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• 2019

The current trend in shipyard industry is to reduce the weight of ships to support the reduction of CO₂ emissions. In this study, the stiffened plate was optimized that is used for building most of the ship-structure. Further, this study proposed the hybrid Genetic Algorithm (GA) technique, which combines a genetic algorithm and subsequent optimization methods. The design variables included the number and type of stiffeners, stiffener spacing, and plate thickness. The number and type of stiffeners are discrete design variables that were optimized using the genetic algorithm. The stiffener spacing and plate thickness are continuous design variables that were determined by subsequent optimization. The plate deformation was classified into global and local displacement, resulting in accurate estimations of the maximum displacement. The optimization result showed that the proposed hybrid GA is effective for obtaining optimal solutions, for all the design variables.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.830-833
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• 2005

SDM(Structural Dynamics Modification) is to improve dynamic characteristics of a structure, more specifically of a base structure, by adding or deleting auxiliary(modifying) structures. In this paper, I will focus on the optimal layout of the stiffeners which are attached to the plate to maximize 1st natural frequency. Recently, a new topology method was proposed by yamazaki. He uses growing and branching tree model. I modified the growing and branching tree model. The method is designated modified tree model. To expand the layout of stiffeners, I will consider non-matching problem. The problem is solved by using local lagrange multiplier without the mesh regeneration. Moreover The CMS(Component mode synthesis) method is employed to reduce the computing time of eigen reanalysis using reduced componet models.

• 한국건축시공학회지
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• 제23권2호
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• pp.209-220
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• 2023

먹매김 로봇은 허용오차 이내의 정밀도를 확보하는 것이 매우 중요하다. 그러나 골조공사는 시공과정에서 철근배근의 변위가 빈번하게 발생하며, 해당오차는 먹선이나 철근위치의 수정을 요구한다. 먹매김 로봇은 정밀도 확보 및 자동화를 위해 철근의 오차를 측정하고 먹선과 철근의 수정을 스스로 판단할 수 있어야 한다. 이에 본 연구는 LiDAR 센서를 통한 철근배근의 오차 측정방안과 이를 바탕으로 먹매김 판단 프로세스를 제시하였다. LiDAR 센서를 활용한 철근인식 실험결과 평균적으로 5mm 내외의 오차를 발생하였으며, 이는 일반적으로 벽체에 적용되는 철근 수준에서 인식을 신뢰할만한 수준으로 나타났다. 또한 철근오차를 범위별로 판단하여 철근의 보정여부와 먹매김의 수행여부를 로봇이 스스로 판단할 수 있는 프로세스를 제시하였다. 본 연구결과는 시공오차를 고려한 먹매김로봇의 자동운영에 기여할 수 있으며 이를 통해 골조품질을 향상시킬 수 있을 것으로 기대된다.