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캐드 기반 범용 최적설계 시스템 개발 및 피로수명을 위한 구조형상최적설계에의 응용
유용균(Yonggyun Yu),곽병만(Byung Man Kwak) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
In this paper, an integrated optimal design software system for structural components has been developed<br/> which interfaces existing commercial codes for CAD, CAE and Optimization. They include specialized<br/> optimal design software codes such as iSIGHT and VisualDOC, optimization module imbedded in CAD<br/> software developed by CAD developers, and optimal design software systems based on API of commercial<br/> CAD software. The advantages of the CAD imbedded optimal design approach and those of specialized<br/> optimal design software are taken to develop the system. The user defines optimal design formulation in the<br/> user interface for problem definition in the CAD control stage, where design variables are directly selectable<br/> from the CAD model and various properties and performance functions defined. The commercial CAD codes,<br/> Open I-DEAS are used for the development. The resulting software is minimally connected to CAD and CAE<br/> systems while keeping maximum independence from each other. This assures flexibility and freedom for<br/> problem definition. Fatigue life optimization is taken as a nontrivial application area. As a specific example,<br/> the shape design of a knuckle part of an automobile is performed, where the minimum fatigue life over the<br/> material domain in terms of the number of cycles of a curb strike are maximized under the constraint of not<br/> exceeding the current mass. The fatigue life has been improved by four times of the initial life. The developed<br/> software is illustrated to maintain the advantages of existing optimal design software systems while improving<br/> independency and flexibility.
유용균(Yonggyun Yu),허재성(Jaesung Huh),Akira Tezuka,곽병만(Byung Man Kwak) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
A procedure is proposed to generate optimal grid with minimal user intervention while keeping a prescribed level of accuracy, using an adaptive X-FEM and applied to shape optimization. In spite of various advantages of X-FEM, however, there are several obstacles for practical applications. Because of using a uniform background mesh and additional degree of freedoms for enrichment, an X-FEM is usually computationally more expensive than traditional finite element method. Furthermore, there are often accuracy problems. For an automatic procedure of optimal mesh generation, an h-adaptive scheme and a posteriori error estimation obtained by a post-processing process are utilized. The procedure is shown by 2-D shape optimization examples.
디지털 트윈 기술을 활용한 음향-진동 배관 시스템의 가상 계측 기술 개발
오승인(Seungin Oh),이강헌(Kang-Heon Lee),안광현(Kwanghyun Ahn),유용균(Yonggyun Yu),김기환(Kihwan Kim),김진균(Jin-Gyun Kim) 대한기계학회 2021 大韓機械學會論文集A Vol.45 No.9
본 연구에서는 유체-고체 연성 배관의 가상센서 시스템을 구성하는 방법을 제안하였으며, 그 신뢰성을 실제 구조물을 대상으로 검증하였다. 제안된 시스템은 유체-고체 연성 배관의 계측되지 않은 변위, 압력, 작용하중 등의 응답을 간접적으로 추정할 수 있다. 대상 구조물의 물리적 특성을 모사하기 위해 음향-진동 유한요소 모델을 활용하였으며, 신뢰성 향상을 위하여 음향-진동 유한요소 모델의 특성을 고려한 업데이팅 기법을 적용하였다. 또한 음향-진동 유한요소 축소모델링 기법을 적용하여, 제안된 가상 센싱 기법의 실시간 적용이 가능하도록 디지털 트윈 모델을 구축하였다. 업데이트 및 축소된 유한요소 모델을 기반으로 시간적분 기법을 적용하여, 구조물 전체의 실시간 응답을 추정할 수 있는 가상 센싱 시스템을 구성하였다. 개발된 기술은 L자형 배관 시험체에서 그 성능을 검증하였다. In this study, we present the framework of a virtual sensing system for a vibro-acoustic structure. The system can estimate the time-transient responses at the unmeasured points of a vibro-acoustic structure, including displacements, pressures, and applied forces. A coupled vibro-acoustic finite element (FE) model is then used as a numerical model of the target structure, and the model is updated using the sensitivity-based FE model updating technique for vibro-acoustic systems. A multiphysics reduced-order modeling approach is then applied to the model to alleviate the computational burden of real-time computation. Based on the pre-processed FE model, a time integration technique is implemented to estimate the unmeasured responses of the target structure. The performance of the suggested virtual sensing system is finally evaluated by implementation on an L-shaped pipe structure.