• 콘크리트학회논문집
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• 제14권4호
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• pp.474-482
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• 2002

본 연구의 목적은 섬유의 부착시험을 통하여 섬유의 파괴없이 최대 인발저항을 가지고 시멘트 모체 내에서 완전한 정착작용을하는 구조용 합성섬유의 최적형상과 최적형상함수를 도출하는데 있다. 7가지 다른 형상의 구조용 합성섬유를 조사하였고 부착시험을 수행하였다. 부착시험의 변수는 7가지의 다른 형상이고, 2종류의 시멘트 모르타르의 배합이다. 부착시험 결과, 7가지 다른 형상중 crimped type이 계면인성(인발에너지)와 인발하중에서 가장 우수한 성능을 보였다. Crimped type을 기본으로 하여 섬유의 주기와 높이를 바꾸어 부착시험을 실시한 결과 최적형상함수, D= $b^{{\alpha}ο{\alpha}}$ $h^{λ{\beta}}$ 를 도출하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.296-303
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• 1996

This paper proposes a method for shape optimization of trusses. The potential savings offered by shape optimization will certainly be more significant than those resulting from fixed-geometry optimization. On the other hand, difficulties associated with topology and geometry optimization are still in existence. Even with a known topology, the geometry optimization problem is still a difficult task. An evolutionary procedure to be adopted and improved in this work, however, offers a means to achieve optimization in topology and geometry together. A plane truss structure is modelled within a specified domain and made to include a great number of nodes and members. Then the structure is analyzed and those members with stresses below a certain level are progressively eliminated from the structural system In this manner the structure evolves into a truss with a better topology and geometry by removing less important parts. Through the worked examples, we can see that the method presented in this Paper shows much promise.

• Structural Engineering and Mechanics
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• 제87권3호
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• pp.243-254
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• 2023

Engineering structures usually suffer from cracks. The crack geometry has an influence on the structural mechanical properties and subsequent crack propagations. However, as an extensively utilized method in fracture analysis, the extended finite element method provided by Abaqus fails to output the specific location and dimensions of fractures. In this study, a technique to capture the crack geometry is proposed. The technique is based on the invariant level set method (I-LSM), which can avoid updating the level set function during crack development. The solution is achieved by an open-source plug-in programmed by Python. Three examples were performed to verify the effectiveness and robustness of the program. The result shows that the developed program can accurately output the crack geometry in both the 2D and 3D models. The open-source plug-in codes are included as supplementary material.

• 한국CDE학회논문집
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• 제4권3호
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• pp.180-189
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• 1999

Solid freeform fabrication technology, widely known as rapid prototyping an rapid tooling, can create physical part directly from digital model by accumulating layers of a given material. Providing a tremendous flexibility of a part geometry that they can fabricate, these technologies present a opportunity or the creation of new products that can not be made with existing technologies. For this to be possible, however, various design environments including different fabrication processes needs to be considered at the time of design, and finding an appropriate design solution for the new product by combining necessary design communications become increasingly complex as environmental condition become diverse. This paper proposes a geometric modeling paradigm for design and fabrication of a new product, honeycomb structural geometry.

• 대한건축학회논문집:구조계
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• 제35권4호
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• pp.167-174
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• 2019

Cable-stayed structures provide a lot of possibilities toward the development of innovative structural forms regarding their expressiveness and uniqueness. Such cable-stayed structures, as form-active structures, can obtain a family of alternatives by changing parameters for defining geometric shapes. The concept of graphic statics is utilized to explain the relationship between the load path and structural forms because the load path of cable structures has something to do with their structural geometry. Moreover, this structural geometry has a dominant effect on both structural efficiency and structural elegancy. The proposed design method in this study will help designers conceive innovative structural forms considering structural safety, material efficiency, and structural art altogether.

• 대한조선학회논문집
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• 제41권2호
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• pp.114-120
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• 2004

Propeller blades have complex airfoil section type geometry and the thickness is continuously varied to both its length and cord-wise direction. in the present research, the finite element analysis program PROSTEC (Propeller Stress Evaluation Code) is developed to calculate the structural responses of propeller blades in irregular ship wake field. To represent the curved and skewed geometry of propeller blades accurately, 20-node curved solid element using the quadratic shape function is adopted. Input data for the analysis including the geometry and pressure distribution of propeller blades can be generated automatically from the propeller design program. And to visualize the results of analysis on windows system conveniently, the post processor PROSTEC-POST is developed.

• Earthquakes and Structures
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• 제2권4호
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• pp.337-356
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• 2011

In this paper, cable-stayed bridges with single pylon and two equal side spans, with variations in geometry and span ranging from 120 m to 240 m have been studied. 3D models of the bridges considered in this study have been analysed using ANSYS. As the first step towards a detailed seismic analysis, free vibration response of different geometries is studied for their mode shapes and frequencies. Typical pattern of free vibration responses in different frequencies with change in geometry is observed. Further, three different seismic loading histories are chosen with various characteristics to find the structural response of different geometries under seismic loading. Effect of variation in pylon shape, cable arrangement with variation in span is found to have typical characteristics with different structural response under seismic loading. From the study, it is observed that the structural response is very much dependent on the geometry of the cable-stayed bridge and the characteristics of the seismic loading as well. Further, structural responses obtained from the study would help the design engineers to take decisions on geometric shapes of the bridges to be constructed in seismic prone zones.

• Bulletin of the Korean Chemical Society
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• 제35권9호
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• pp.2738-2742
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• 2014

Geometry relaxation effects on the formation of benzene excimer were investigated by means of ab initio calculation at SOS-CIS($D_0$)/aug-cc-pVDZ level. In the case of T-shaped dimer configuration, intermolecular interactions in the excited states are found to be nearly the same as those in the ground state and structural deformations are limited within a single molecule; the geometry relaxation effects are then negligible and singlet-triplet energy gap remains constant. As for face-to-face eclipsed dimer, on the other hand, both molecules undergo structural change. As a result, intermolecular interactions in the excited states are significantly different than those in the ground state. Although the intermolecular distances obtained from potential energy curve calculation with frozen molecular structures are in qualitative agreement, the excited-state binding energies are notably overestimated with respect to those at optimized structures. In particular, the effects are calculated to be larger in $T_1$ state and hence singlet-triplet energy gap, which reduces markedly in this configuration, is underestimated without relaxation.

• 한국전산구조공학회논문집
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• 제30권2호
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• pp.103-110
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• 2017

본 논문에서는 StrAuto를 이용하여 구조물의 형상 변경을 통한 대안을 생성하고, 이에 대한 최적화를 수행하는 과정을 상세하게 다루었다. 비정형 대공간 전시장 구조물을 대상으로 전체 형상을 파라메트릭하게 디자인하고, 가장 폭이 넓은 경간의 구조 형상을 변경하면서 물량 변화를 관측하여 최적안을 도출하였다. 기존 연구들에서는 형상 변경의 제약 때문에 대부분 단면과 물성을 통한 최적화를 수행하는데 그쳤으나, 본 연구에서는 형상 변경이 가능한 부분을 찾아내어 StrAuto의 가장 핵심적인 능력인 형상 변경을 통한 최적화를 수행했다는 점에서 중요한 의미를 지닌다. 형상 변경으로 충분한 여유를 확보하고 단면 최적화로 물량을 줄이는 프로세스를 통해, 대공간 구조물의 일부만을 대상으로 하면서도 전체 물량의 11.7%를 줄일 수 있었다.

• Computers and Concrete
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• 제13권2호
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• pp.271-290
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• 2014

In this study, structural irregularities in plan, which has a considerable effect on earthquake behavior of buildings, have been investigated in detail based on Turkish Earthquake Code 2007. The study consists of six main parametric models and a total of 144 sub-models that are grouped based on RC structural systems such as frame, frame + rigid core, frame with shear wall, and frame with shear wall + rigid core. All models are designed to have both symmetrical plan geometry and regular rigidity distribution. Changes in the earthquake behavior of buildings were evaluated according to the number of storeys, number of axes and the configuration of structural elements. Many findings are obtained and assessed as a result of the analysis for each structural irregularity. The study shows that structural irregularities can be observed in completely symmetric buildings in terms of plan geometry and rigidity distribution.