• 소성∙가공
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• 제12권4호
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• pp.401-407
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• 2003

This paper newly proposes a mesh regularization method for the enhancement of the efficiency in sheet metal forming analysis. The regularization method searches for distorted elements with appropriate searching criteria and constructs patches including the elements to be modified. Each patch is then extended to a three-dimensional surface in order to obtain the information of the continuous coordinates. In constructing the surface enclosing each patch, NURBS(Non-Uniform Rational B-Spline) surface is employed to describe a three-dimensional free surface. On the basis of the constructed surface, each node is properly arranged to form unit elements as close as to a square. The state variables calculated from its original mesh geometry are mapped into the new mesh geometry for the next stage or incremental step of a forming analysis. The analysis results with the proposed method are compared to the results from the direct forming analysis without mesh regularization in order to confirm the validity of the method.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.510-513
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• 2005

Due to the asymptotic property, deadbeat control can hardly be applied to the continuous time system control. But some delay element method can deal such a problem. Besides delay element method, well-known digital deadbeat control can be used by the aid of some smoothing elements. In this paper, 2nd order smoothing element is used for the smoothing of the digital deadbeat controller. And this element is argumented to the plant, and so control problem is to control the argumented system digitally. We simulated this control system using Matlab language and finally apply this algorithm to the rotary inverted pendulum system.

• Steel and Composite Structures
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• 제5권4호
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• pp.305-326
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• 2005

The inelastic buckling behaviour of continuously restrained two and three-span continuous beams subjected to concentrated loads and uniformly distributed loads are studied in this paper. The restraint type considered in this paper is fully restrained against translation and elastic twist applied at the top flange. These types of restraints are most likely experienced in industrial structures, for example steel-concrete composite beams and half through girders. The buckling analysis of continuous beam consists of two parts, firstly the moment and shear distribution along the member are determined by employing force method and the information is then used for an out-of-plane buckling analysis. The finite element method is incorporated with so-called simplified and the polynomial pattern of residual stress. Owing to the inelastic response of the steel, both the in-plane and out-of-plane analysis, which is treated as being uncoupled, extend into the nonlinear range. This paper presents the results of inelastic lateral-torsional and lateral-distortional buckling load and finally conclusions are drawn regarding the web distortion.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권6호
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• pp.306-313
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• 2006

A three dimensional adaptive finite element refinement algorithm is developed for non-linear magnetostatic field problems. In the method, the edge elements are used for finite element formulation, and the local error in each element is estimated from the fact that the tangential components of magnetic field intensity and the normal components of magnetic flux density should be continuous at the interface of the two adjacent elements. Based on the estimated error, the elements which have big error are divided into several elements using bisection method. The effectiveness of the developed algorithm is proved through numerical examples.

• 한국건축시공학회지
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• 제13권3호
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• pp.291-305
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• 2013

This paper presents the continuous hoop reinforcement method as a means to overcome the difficulty of rebar construction due to the seismic detail of lateral reinforcement. Because the continuous hoop has no seismic hook, and there is less interference during the rebar work, rebar quantities and construction time can be reduced. Since the details of column and beam continuous hoops are different from those of conventional lateral reinforcements, the construction method should be developed through mock-up tests. The length of the beam mock-up is 8m and the section size is $500mm{\times}700mm$, the height of the column mock-up is 2.8m and 4m, and the section size is $800{\times}800mm$. The length and the size are determined based on the elements that are generally used in reinforced concrete basement parking lots and office buildings. The results of the mock-up test showed that the quantities of rebar could be reduced by 20% and the time could be reduced by up to 40% compared with conventional lateral reinforcements.

• 대한기계학회논문집A
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• 제28권3호
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• pp.215-221
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• 2004

Large machine and structure can not be normally treated as lumped parameter system. Such machine or structure must be broken down to individual beams or panels the motion of which must be analysed before an absorber system can be designed for each element. The absorber may be a lumped parameter system or a continuous system. One of the most common elements in a machine or structure is the cantilever, and in this paper is considered the design of a continuous parameter absorber to reduce the transverse vibrations of a beam. So this paper describes the method to obtain the accurate information about combined continuous beam system with DVA. This information is obtained from the combined system's receptance. and this paper shows the convenience and useful informations when design the dynamic vibration absorber with the combined system's receptance.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.210-217
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• 1996

Under strong shock loads including earthquake or blast, structures may start to crack in stress concentrated members. The continuous behavior of the structure changes to the discontinuous. In this study, numerical method analyzing continuous and discontinuous behavior of a structure is developed using a modified distinct element method. Equations of motion of each distinct element are integrated using the central difference method, one of the finite difference methods. Interactions between he elements are considered by an element and pore spring. The forces acting in the center of an element include contact stress transferred by element spring; tensile stress by pore spring; and external traction such as earthquake or blast load. To verify the proposed method, the behavior of the cantilever beam subject to the quasi-static concentrated force at the end is investigated. The failure behavior of the simply supported beam subject to the strong shock at the center is studied. The proposed method can predict the failure behavior of the structure due to the shock loading and the post-failure discontinuous behavior of the structure.

• Earthquakes and Structures
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• 제11권1호
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• pp.45-61
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• 2016

Structures with soft story irregularity have been seriously damaged in earthquakes. Therefore, the analysis of dynamic behavior of structures with soft story irregularity is of great value and relevance. In this study, a certain method will be used to discover the displacements and internal forces and to find out results about soft story irregularity. For this study, the multi-story frame-hinged shear wall system has been used as a model according to the continuous calculation system. The dynamic characteristics of the system have been obtained by analyzing the governing differential equation of the system. The dynamic characteristics have been calculated for a practical and quick analysis as indicated in tables. The suggested method is wholly based on manual calculation. A spectral analysis can be easily conducted with the help of Tables provided by this study. A sample has been solved and compared to the finite elements method to study the suitability of the method suggested at the end of this study.

• 조명전기설비학회논문지
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• 제18권6호
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• pp.108-113
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• 2004

점근특성 때문에 deadbeat제어는 연속계시스템에는 거의 적용이 불가능하다. 그러나 지연요소법은 이런 문제를 해결할 수 있다. 지연요소법외에도 잘 알려진 디지털 deadbeat제어가 평활요소를 추가하여 사용될 수 있다. 본 논문에서는 2차 평활요소를 디지털 deadbeat제어기에 사용한다. 그리고 이 요소는 플랜트에 확장되고 따라서 확장된 시스템을 디지털제어하게 된다. 이 제어시스템을 Matlab언어를 사용하여 회전형 도립진자 시스템에 적용하여 시뮬레이션한다.

• 한국농촌건축학회논문집
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• 제12권1호
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• pp.57-64
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• 2010

This study is to clarify the actual conditions of high school of environment friendly architecture per ecological environment elements through extracting ecological environment elements which is possible to analyze in quantity certification standards of environment friendly architecture. As the method of the study, First, certification as an examination on certification system of environment-friendly architecture, summary of certification system of environment friendly architecture and certification high school, ecological environment elements which is possible for quantitative analysis of ecological environment certification standards were extracted. Second, actual condition of ecological environment elements per non-certification high school by collecting actual data of certification schools environment friendly architecture were analyzed and the results are as the follows. The average of ecological area ratio was 17.8 percent in case of non-certification school facilities it was analyzed that the natural based green area ratio was 17.5 percent, continuous green axis length ratio was 19.0 percent and roof green garden area ratio was 0 percent.