• Journal of the Korean Society for Precision Engineering
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• v.15 no.12
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• pp.21-27
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• 1998

This paper recommends the database construction for STL data and the new method of Delaunay's triangulation method in order to decrease volume errors by verifying STL file errors and modifying hole errors. Each vertex for the boundary coordinates of the verified hole errors was analyzed according to the following cases: planes or slow curves, edges, apexes, and rapid curves. In each case, a different modification process was adopted. With this method, most errors resulting from the conversion into the STL data as well as lots of volume errors arising from error modification were decreased.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.10a
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• pp.179-184
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• 2004

This paper presents a prototype of document schema to guarantee the consistency of the bridge design information during the life-cycle of bridge. The main component of document schema for bridge design information is derived from the Document Type Definition (DTD) Pool which is the Construction CALS/EC standard in Korea and the document schema is implemented by using the XML Schema. The ifcXML are adopted for representing product data of bridge. A pilot system adopting the document schema and its application to existing bridge show that the suggested document schema can be efficiently used to develop software modules supporting the integrated design documents for bridges.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1989.10a
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• pp.51-58
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• 1989

Through a series of analyses of specific structures it is shown that incremental collapse may be the critical design criterion and that shakedown analysis can be used as a design tool. Using shakedown analysis technique, a nonlinear structural optimization program has been developed. This incorporates : (ⅰ) design constraints on elastic stresses and deflections ; (ⅱ) constraints for the prevention of incremental collapse and soft story failure ; and (ⅲ) the constraint on the fundamental period of structure. A five-step design procedure is proposed by using this program to obtain the optimum design that satisfies all the requirements of comprehensive earthquake-resistant design.

• Journal of the korean Society of Automotive Engineers
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• v.17 no.5
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• pp.1-8
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• 1995

전산유체 해법의 내연기관 3차원 해석에 대한 최근 연구 동향에 대해 소개하였다. 난류유동 해석은 아직 정확성과 신뢰도 면에서 많은 연구가 필요하지만 현재의 상태에서도 직관, 경험, 실험 측정에 의해 파악하기 어렵거나 많은 비용과 시간이 요구되는 부분을 보완해 줄 수 있는 도구로서 인정받고 있다. 연소해석 부분은 현상 자체가 유동, 연소, 분무, 열전달등이 복합적으로 작용하는 어려운 문제로서 공학계산의 가장 첨단 분야 중의 하나라 할 수 있다. 현재 관련 모델로서 스파크 점화기관의 점화 및 화염전파, 배기가스 생성 과정과 디젤기관의 압축착화, 예혼합 및 확산 연소, 매연 등의 생성과정에 대한 모델 개발과 검증이 활발히 이루어지고 있다. 일부 발표된 논문 결과들은 이와 같은 방법이 엔진의 주요 연소 특성을 재현하는데에 성공적으로 활용될 수 있음을 보여주고 있다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1998.10a
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• pp.342-351
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• 1998

The purpose of this study is to develop a central database and a database management system to store and manage information systematically from each module of an integrated structural design system. In order to efficiently express structural design process related to the data which is very complex, we used an object-oriented modeling methodology to propose the possibility to apply a database schema for application programs in an integrated system for reinforced concrete structural design. Based on this model, we developed an interface between each module and central database. After modeled by using object modeling technique, the database was mapped by the relational database table. Then the central database and the interface were programed by using Visual C/syo ++/, a windows environmental development tool.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1997.10a
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• pp.171-178
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• 1997

This paper describes the application of discretized continuum-type optimality criteria (DCOC) for the multispan partially prestressed concrete beams. The cost of construction as objective function which includes the costs of concrete, prestressing steel, non-prestressing steel and formwork is minimized. The design constraints include limits on the maximum deflection, flexural and shear strengths, in addition to ductility requirements, and upper and lower bounds on design variables as stipulated by the design code. Based on Kuhn-Tucker necessary conditions, the optimality criteria are explicitly derived in terms of the design variables-effective depth, eccentricity of prestressing steel and non-prestressing steel ratio. The prestressing profile is prescribed by parabolic functions. The self-weight of the structure is included in the equilibrium equation of the real system, as is the secondary effect resulting from the prestressing force. Two numerical examples of multispan PPC beams with rectangular cross-section are solved to show the applicability and efficiency fo the DCOC-based technique.

• Computational Structural Engineering
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• v.12 no.1
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• pp.27-34
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• 1999

독자적인 자동차 충돌해석용 프로그램 개발 및 응용기술을 목표로 Explicit 수식화, 셀 요소의 정식화, 교체요소의 정식화, 비선형스프링 요소의 개발, 초탄성 고무재료의 개발, Hourglass 제어, 접촉알고리즘 정식화 등의 프로그램의 기본 모듈을 구성하였고, 그래프 출력용 포스트 프로그램을 개발하였다. 비선형스프링, 에어백 모듈, 안전벨트 모듈 등이 개발되었으며, 자체구조물들의 정면·측면 충돌해석을 수행하고 상용충돌해석프로그램들과 그 결과를 비교하여 개발된 프로그램의 신뢰성을 확인하였다. 또한, 측면충돌 모델을 사용하여 설계초기단계에서 빠른 해석을 수행할 수 있도록 하는 Hybrid 모델링 기법을 개발하여 기존의 쉘모델의 결과와 비교·검토하였다. Hybrid 모델링시 조인트 부의 특성을 측면해석 모델에 적용하여 그 타당성을 검증하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2015.10a
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• pp.105-106
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• 2015

EDISON은 5개 전문응용분야(전산열유체, 나노물리, 계산화학, 구조동역학, 전산설계)로 구성되어 있으며, 계산과학공학의 교육 연구 활성화를 위하여 2011년부터 제공하고 있는 사업이다. 본 연구는 EDISON 계산화학 전문분야를 중심으로 현재 활발히 제공하고 있는 SW 및 사용자 활용 현황을 분석하여, EDISON 시스템을 확산할 수 있는 방안을 제언하였다.

• Computational Structural Engineering
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• v.7 no.2
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• pp.121-129
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• 1994

The Finite Element Method(FEM), which is existing stress analysis method, requires substantial amounts of efforts for analysis of perforated plates. An equivalent solid plate analysis method is developed in this paper. A perforated plate is assumed to be an equivalent solid plate in this method. Stress analysis is performed for this equivalent solid plate using effective material properties, and then these stresses are converted to the actual stresses of the original perforated plate. A case study is conducted for a rectangularly arrayed perforated plate using the proposed method in this paper. Compared and analyzed with respect to those calculated by the existing stress analysis method, the result seems to be satisfied in terms of its practicality and more conservative with respect to margin in design application.

• Computational Structural Engineering
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• v.9 no.2
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• pp.93-101
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• 1996

An artificial neural network is a computational model that mimics the biological system of the brain and it consists of a number of interconnected processing units where it can reasonably infer by them. Because the neural network is particularly useful for evaluating systems with a multitude of nonlinear variables, it can be used in experimental results predictions, in structural planning and in optimum design of structures. This paper describes the basic theory related to the neural networks and discusses the applicability of neural networks to predict the ultimate shear capacity of the precast concrete vertical joints by comparing the neural networks with a conventional method such as regression.