• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.5
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• pp.645-652
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• 1986

For the analysis of equi-biaxial tension, the Lankford values at the various strain levels were measured experimentally at first. It was clarified that the R values depend on strain to a great extent and based on this result, the analysis of the equi-biaxial tension was carried out. Hill's new yield criterion was used to predict the stress-strain curves theoretically. The value of new parameter, m for the coincidence of the theory with the experiment was 2.1. It is desired that the optimum R-value in the case of m=2.1 is measured at strain, 15% for the reasonable correlation between theory and experiment.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.6
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• pp.587-596
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• 2009

The fiber bridging model is the crucial factor to predict or analyze the tensile behavior of fiber reinforced cementitious composites. This paper presents the fiber bridging constitutive law considering the distribution of fiber inclined angle and the number of fibers in engineered cementitious composites. The distribution of fiber inclined angle and the number of fibers are measured and analyzed by the image processing technique. The fiber distribution are considerably different from those obtained by assuming two- or three-dimensional random distributions for the fiber inclined angle. The simulation of the uniaxial tension behavior was performed considering the distribution of fiber inclined angle and number of fibers measured by the sectional image analysis. The simulation results exhibit multiple cracking and strain hardening behavior that correspond well with test results.

• Journal of Korean Society of Steel Construction
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• v.19 no.2
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• pp.201-210
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• 2007

Double-angle connections should be designed with enough stiffness and strength to properly resist various applied loads. Therefore, structural engineers should be able to predict some influential variables and take their effects into account in design. This study was performed to establish the effects of the number of bolts and bolt gage distance on the stiffness and strength of a double-angle connection under tension. Six experimental tests were conducted to describe the effects of these variables by comparing load-displacement relationship curves. In addition, two prediction models were proposed to estimate the initial stiffness and the maximum allowable tensile load based on the results of experimental tests. In the development of these prediction models, the effect of prying action was considered.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.67-73
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• 2011

This study aims to develop an economical precast hollow concrete column with high constructability which consists of only splice sleeve and general reinforcing bar without using PC tendons in order to reduce the construction period and cost. With this purpose, this study performed the finite element analysis and tension test by using some variables such as length of sleeve, diameter of rebar and curing method for suggesting a grouting type splice sleeve which is a new type joint rebar and developing an optimized splice sleeve. As a result, the analysis on the tension performance of splice sleeve did not show any destruction caused by pull-out in reinforcing bar but it only occurred destruction of tension bar or bolt shear rupture from the mechanical defect of sleeve. Therefore, the experiment showed high performance in tension of the suggested splice sleeve and verified the application of precast hollow concrete column.

• Journal of Powder Materials
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• v.16 no.2
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• pp.138-145
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• 2009

The combination of focused ion beam (FIB) and 4 point probe nanomanipulator could make various nano manufacturing and electrical measurements possible. In this study, we manufactured individual ZnO nanowire devices and measured those electrical properties. In addition, tensile experiments of metallic Au and Pd nanowires was performed by the same directional alignment of two nanomanipulators and a nanowire. It was confirmed from I-V curves that Ohmic contact is formed between electrodes and nanomanipulators, which is able to directly measure the electrical properties of a nanowire itself. In the mechanical tensile test, Au and Pd nanowires showed a totally different fracture behavior except the realignment from <110> to <002>. The deformation until the fracture was governed by twin for Au and by slip for Pd nanowires, respectively. The crystallographic relationship and fracture mechanism was discussed by TEM observations.

• Journal of the Korea Concrete Institute
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• v.15 no.1
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• pp.60-68
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• 2003

Tension tests of six half-thickness concrete containment wall elements were conducted as a part of Korea Atomic Energy Research Institute (KAERI) program. The aim of the KAERI test program is to provide a test-verified analytical method for estimating capacities of concrete reactor containment buildings under internal overpressurization from postulated degraded core accidents. The data from the tests reported herein should be useful for benchmarking analytical method that require modeling of material behavior including concrete cracking behavior and reinforcement/concrete interaction exhibited by the test. Major test variable is compressive strength of concrete, and its effect on the behavior of prestressed concrete panel subjected to biaxial tension is investigated.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1996.11a
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• pp.3-11
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• 1996

본 연구는 고체 추진기관의 각종 밀봉 부에 많이 사용되는 O-링의 설계시 고려되는 각종 형상인자의 변화에 따른 O-링의 거동과 응력 상태를 분석하여 설계 최적조건을 찾기 위한 내용을 다루고 있다. 조립 부의 내외경과 조립 공차, 챔퍼길이와 각도, 조립 홈의 외경, 깊이, 폭, 구성반경, O-링의 내경과 선 직경 등의 설계 변수에 의한 조립부 형상과 재료의 물성치, 유한요소 선택 및 요소 분할, 경계조건, 하중조건, 접촉부 정의 등을 MSC/PATRAN3의 $PCL^{[1]}$/로 프로그래밍 하여 설계변수에 의한 결과 분석을 손쉽게 수행할 수 있도록 시도하였다 고무의 Hyperelastic 물성치는 문헌상의 자료$자료^{[2]}$에 제시된 Ogden 상수를 사용하였으며 추후에는 인장시험, 순수전단시험, 이 축 인장시험을 통해 실험적으로 측정$^{[3]}$ 하여 적용할 예정이다. 고무의 대변형, 대 변형률을 고려한 비선형 응력해석은 MSC/PATRAN3의 Advanced FEA 모듈과 ABAQUS 5.5를 사용하였다. 본 연구에서의 해석결과를 설계변수들의 영향을 비교 분석하는데 사용하였으나 그 정확도가 입증된 상태는 아니며 추후 실제 조립 및 수압시험을 통해 평가할 예정이다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.933-936
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• 2008

An engineered cementitious composite (Engineered Cementitious Composite) had been developed in previous study. Theoretical prediction of the tensile stress-strain relation of ECC is important in providing the material constitutive relation necessary for designing structural members. But, few studies have been reported with regard to predicting the tensile stress-strain relation of ECC. Prediction of the tensile stress-strain relation of ECC accounting for actual bridging curve, such as fiber dispersion is needed. The present study extends the work as developed by Kanda et al., by modeling the bridging curve, accounting for fiber dispersion, the degree of matrix spalling, and fiber rupture to predict the tensile stress-strain relation of ECC. The role of material variation in the bridging curve, such as number of effective fiber actually involved in the bridging capacity and how it affects the multiple cracking process is discussed. The approach for formulating the tensile stress-strain relation is discussed next, where the procedure for obtaining the necessary parameters, such as the crack spacing, is presented. Finally, the predicted stress-strain relation will be validated with experimental tests results.

• Magazine of the Korea Concrete Institute
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• v.4 no.2
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• pp.111-118
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• 1992

본 연구는 실리카흄을 혼화재료로 사용하여 1200kg/$ extrm{cm}^2$정도의 초고강도 콘크리트를 제조하였으며 이에 대한 재료특성을 실험 및 보부재의 휨거동을 실험을 실시 비교 분석하였다. 재료특성 실험으로는 기본적인 강도 시험, 파괴음 측정에 의한 AE실험 그리고 수은압입법에 의한 세공실험을 실시하였다. 초고강도 콘크리트의 재료특성치는 ACI 363의 고강도 콘크리트 재료특성 결가보다 크게 나타났으며 압축강도와 미세공극량은 선형적으로 비례하였다. 보부재의 휨특성을 파악하기 위해 인장철근비 변화, 전단보강근의 유무 및 철근 표면형상의 변화 등을 실험인자로 하였으며 각각의 현상을 비교분석함으로써 균열성상에 따른 하중-변위 관계, 중립축 이동에 따른 부재거동 및 응력블록의 변화에 관하여 비교 고찰하였다. 초고강도 콘크리트 사용한 보부재의 경우 중립축 상승으로 단면의 압축영역은 매우 작아져 급격히 압축파괴되는 경향을 보였으며 응력블록 형태는 삼각형의 분포를 보였다.

• Journal of Korean Society of Steel Construction
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• v.27 no.2
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• pp.251-260
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• 2015

The end plate connection is applied to beam-column moment connections in various forms. Such end plate connection displays changes in the behavioral characteristics, strength and stiffness, and energy dissipation capacity based on the thickness and length of the end plate, the number and diameter of the high strength bolt, the gauge distance of the high strength bolt, prying action force of the high strength bolt, and dimensions and length of the welds. Accordingly, this study has apprehended the axial tensile stiffness and prying action force of the high strength bolt connected on the tensile side based on the difference in thickness of the end plate, and was conducted to propose an analysis model for the prediction of such variables that affect the operating properties of the end plate. To achieve this, this study has conducted a three-dimensional non-linear finite-element analysis of the unstiffened expanding end plate connection by selecting only the thickness of the end plate as the variable.