• Journal of the Korean Wood Science and Technology
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• v.45 no.1
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• pp.53-61
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• 2017

In this study, specimens were produced with a column member and a wooden gusset only by inserting an wooden gusset which is a substitute for steel plate into the center of a slit-processed column member. The moment resistance performance of the specimens was compared with that of control specimens that used a steel plate. The measured maximum moments of the specimens produced with GFRP-reinforced wooden laminated gussets and pins were lower by 24% on average compared to the steel plate-inserted specimens, but they showed good toughness. The fracture shape suggests that it was fractured along the annual rings between the pin and the end of the column member. The rigid specimen that integrated a laminated wood and a wooden laminated gusset with adhesive showed 2.8 times greater initial rigidity and 40% greater maximum moment on average compared to the control specimen. The rigid specimens mainly fractured on a glulam around glue line.

• Journal of Korean Society of Steel Construction
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• v.26 no.4
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• pp.335-348
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• 2014

For high-strength steel, it is difficult to be applied to flexible structural member because it have high yield ratio and low basic material's toughness. One of the great problems when using high-strength steel connections is the brittle fracture at the end of the beam member in common with general mild steel connections. In the cases of mild steel connections, it has be developed that special moment frame connection details by reinforcing structural member or improvement of welding access hole. But, it is incomplete at yet about applicability estimation of high-strength steel connections. This study is the initial step research for the applicability estimation of beam-to-column connections being applied to developed high-strength steel, HSA800. And, it studied about structural performance of the high-strength steel connections according to the details of welding access hole through full-scale test and analytical method.

• Magazine of the Korea Concrete Institute
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• v.6 no.2
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• pp.97-107
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• 1994

The objective of this study is to develop polymer-impregnated concrete(PIC), which is a newly developed composite material made by impregnating polymer impregnanls into hardened normal concrete, and to develop analytical techniques for its proper applications. Crystalline methyl methacrylate(MMA) is chosen as a monomer of polymer impregnants. The corrlpositions of polymer impregnants and producing processes are developed by analyzing the effects of penetration, polymerization, thermal safety, and strengthening characteristics. On t he basis of experimental results of this study, various strength characteristics and stress strain constitutive relations are formulated in terms of the compressive strength of normal concrete and the polymer loadings, which can be applied for analysis and design of PIC members. In order to provide a model for fracture analysis of flexural members, fracture toughness, fracture energy, critical crack width, and tension softening relations near crack tip are also formulated in terms of member depth, initial notch depth, and the flexural strength of normal concrete. The structural analysis procedure and the finite element computer program developed in the study are applicable to evaluate elastic behavior, ultimate strength, and tension softening behavior of MMA type PIC structural members subject to various loading conditions. The accuracy and effectiveness of the developed computer program is examined by comparing the anal ytical results with the experimental results. Therefore, it is concluded that the developed structural analysis procedure and the finite element computer program are applicable to analysis and design of in-situ and precast PIC structural members.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.463-468
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• 2001

A lot of considerations on the spatting by fire of high performance concrete should be taken into for fire resistance of the concrete structures. In this paper, fire resistance of high performance concrete is described using polypropylene fiber, which is known to be contributed to fire resistance. Strength level and member size are varied with. According to test results, spatting by fire takes place more easily, as W/C increases and member size decreases. It shows that concrete containing polypropylene fiber has good effects on preventing spatting by fire. In case high performance concrete does not contain polypropylene fiber, residual strength shows to be decreased remarkably compared :o that of normal concrete. Whereas, in case 0.1% of polypropylene fiber contents, high performance concrete shows higher residual strength than that of normal concrete. As member size is smaller, residual strength shows to be decreased.

• Journal of Welding and Joining
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• v.10 no.4
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• pp.44-57
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• 1992

본 보에서는 용접 구조물의 파괴 방지를 위한 제반 용접 구조 설계에 대하여 전반적으로 기술 하였다. 현대 용접 구조물의 각 선급이나 spec.에서 규정한 식들에 의해 산정된 정적하중으로 구조 설계되는 종래의 방법과는 달리, 유한 요소 구조 해석에 의한 강도 평가, 외부하중의 직접 계산에 의한 보다 정확한 설계 하중의 설정 및 통계적 처리를 통한 합리적인 구조해석(피로강도 포함)등으로 설계되고 있다. 더우기 구조설계시 구조물의 취성파괴를 고려한 파괴강도 및 인성 개념을 도입하였을 뿐 아니라 균열의 존재와 성장을 파괴 역학적으로 해석하여 구조물의 조업 중에서의 파괴관리 및 제어도 실시할 수 있는 총합적인 설계에 의하여 용접 구조물은 제작되고 있다. 비록 구조물의 총합적인 구조 설계로 제작되었을지라도, 구조물의 사용 성능은 용접부의 특성에 의하여 크게 변하게 되므로 용접 설계의 역할을 매우 중요하다. 용접 설계란 용접시공법, 구조부재 및 용접재료의 선정, 용접 이음부의 구조적 형상과 세부 형상 및 그외 용접에 관련된 제 인자들을 상호 유기적으로 조합함으로써 보다 경제적이고 신뢰성 있는 용접부를 얻고자 함에 그 목적이 있다.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.159-160
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• 2010

Due to the characteristics of high toughness, FRP is a valuable material to apply to the structures that have to withstand the blast or impact loads. FEM analyses for the concrete beams flexurally strengthened in tension part with FRP sheets were performed to improve the low-velocity impact resistance.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.714-717
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• 2013

스마트폰의 대중화로 현재 앱스토어에는 다양한 어플리케이션들이 나오고 있다. 이와 같이 급속하게 발전하는 시대임에도 불구하고 모바일디바이스에서 웹페이지 또는 어플리케이션 으로 확인 할 수 있는 표준정보의 부재가 심각하다. 본 논문에서는 확인하기도 힘들고 활용하기도 어려운 기술표준 관련 정보를 공공안내그림표지 OpenAPI를 활용하여 보다 쉽게 이용 가능한 iOS 기반 스마트폰 어플리케이션을 설계 및 구현한다.

• Journal of the Korea Institute of Building Construction
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• v.13 no.5
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• pp.465-473
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• 2013

Concrete is an outstanding material in terms of its impact and blast resistance performance. However, there a limitation of concrete is its risk of collapse due to the brittle failure and spalling. Increasing the thickness of members was used as a method to enhance the protective performance of concrete, despite the resulting inefficient space. To solve this problem, different types of fiber reinforced concrete were developed. Recently, another type of fiber reinforced concrete is also being developed and applied as a material that offers protection against impacts and blasts by increasing the flexural toughness of concrete. In this study, the test was conducted to evaluate the impact resistance performance of fiber reinforced concrete and mortar according to impact of high-velocity projectile. A concrete T-wall was also tested to evaluate its protective performance from fragment by 155mm-thick artillery shell. The test results revealed that improving flexural strength through fiber reinforcement inhibited cracks and spalling of rear, and spalling of front by high-velocity impact. As such, it is expected to improve the protective performance of the T-wall and reduce the thickness of the member.

• Journal of The Korean Association For Science Education
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• v.15 no.4
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• pp.487-494
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• 1995

본 연구는 우리 나라의 성인들이 자신의 초중등 학교 시절 경험하였던 학교 과학교육에 대해 어떤 종류의 즐거운 혹은 괴로운 기억들을 현재까지 갖고 있는가를 탐색하였다. 성인들은 오래 전 경험하였던 매우 인상적인 활동이나 장면들을 통해 학교 과학교육을 기억할 것이고, 이러한 기억은 그들의 학교 과학교육에 대한 전반적인 태도에 결정적인 역할을 할 것이다. 따라서 성인들의 학교 과학교육에 대한 이러한 기억들을 살펴보면, 학교 과학교육의 특징을 이해하고 장기적으로 학교 과학교육을 보다 즐거운 경험의 장으로 만드는 데 도움이 될 것이다. 본 연구는 소규모의 설문 조사를 통해 이루어졌으며, 설문 대상은 대구지역의 30-50대 성인 88명이었다. 설문은 현재 과학과 관련된 특정한 직업을 갖고 있지 않은 사람을 대상으로 하였으며, 설문에서 응답자들은 자신들의 초중등 학교 과학교육을 받으면서 가장 즐거웠던 기억과 가장 괴로웠던 기억이 구체적으로 무엇이며 이러한 경험은 초중고 어느 때이었는가를 응답하였다. 성인들이 가장 즐거웠던 기억으로 지적한 것은 실험 실습 활동(65.9%), 야외학습 활동(19.3%) 등으로 전통적인 교실수업 이외의 활동이 약 86%로 나타났다. 그리고 효과적인 교실수업, 교사의 인성적 특징, 과학전람회 참가 등의 경험을 언급한 경우도 부분적으로 있었다. 성인들이 가장 괴로웠던 기억으로 지적한 것은 따분한 교실수업(51.1%), 실험 실습 활동의 부정적인 측면(28.4%) 등으로 나타났으며, 부분적으로 과다한 숙제, 교사의 인성적 특징, 야외학습 활동, 과학수업의 부재 등을 지적한 경우도 있었다. 또한 전체적으로 즐거웠던 기억은 국민학교 시절의 경험에서(56.8%), 반면 괴로웠던 기억은 고등학교 시절의 경험에서(44.3%) 많이 나타났다. 특히, "개구리 해부 실험" 의 경우, 7명이 가장 즐거웠던 기억으로 8명은 가장 괴로웠던 기억으로 언급하여 매우 상반된 견해를 나타냈다. 따라서 동일한 활동일지라도 학생들에게는 매우 상반된 경험으로 작용하게 되며, 이 경우 생명체에 대한 과학실험의 윤리적 문제와 이에 대한 갈등을 분명하게 드러냈다.

• Fire Science and Engineering
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• v.27 no.5
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• pp.26-31
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• 2013

In nuclear power plant, anchor bolts for pressurizer supports are sufficiently used in terms of safety reason, but field inspections have reported that some bolts exceed the limit of their allowable hardness. Because the high level of hardness may lead to failures due to the stress corrosion or fracture toughness, a regular inspection is required for the bolts in nuclear power plant. Thus, this research measures the hardness of bolts currently used in pressurizer supports and then estimates maximum allowable stresses preventing failures by stress corrosion and fracture toughness. Using the ANSYS program, the stresses of the bolts in the regular condition and accidental condition have been calculated, and the possible maximum stress has been compared with the estimated allowable stresses. From the results, the stresses of bolts in the accidental condition satisfy the allowable safety stress from the stress corrosion failure. However, in the future, it shall be needed to consider the reflection of the structure assembling method on the assembling procedure to ensure the pressurizer integrity during maintenance period time.