• Computers and Concrete
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• 제7권2호
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• pp.191-202
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• 2010

A laboratory investigation was conducted to characterize the constitutive property behavior of Cor-Tuf, an ultra-high-performance composite concrete. Mechanical property tests (hydrostatic compression, unconfined compression (UC), triaxial compression (TXC), unconfined direct pull (DP), uniaxial strain, and uniaxial-strain-load/constant-volumetric-strain tests) were performed on specimens prepared from concrete mixtures with and without steel fibers. From the UC and TXC test results, compression failure surfaces were developed for both sets of specimens. Both failure surfaces exhibited a continuous increase in maximum principal stress difference with increasing confining stress. The DP tests results determined the unconfined tensile strengths of the two mixtures. The tensile strength of each mixture was less than the generally assumed tensile strength for conventional strength concrete, which is 10 percent of the unconfined compressive strength. Both concretes behaved similarly, but Cor-Tuf with steel fibers exhibited slightly greater strength with increased confining pressure, and Cor-Tuf without steel fibers displayed slightly greater compressibility.

• 한국해양공학회지
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• 제20권1호
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• pp.7-15
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• 2006

In this research, the behavior characteristics of cement mixing lightweight soil (CMLS) for recycling of dredged soil in the Nakdong River estuary are experimentally investigated. CMLS is composed of the dredged soil from Nakdong River estuary, cement, and air foam. For this purpose, uniaxial compression tests are carried out for artificially prepared specimens of CMLS, with various initial water contents, cement contents, and mixing ratio of dredged soils. The experimental results of CMLS indicated that the compressive strength is strongly influenced by the cement contents, rather than water contents and air foam. Compressive strength of CMLS increased with an increase in cement content, while it decreased with an increase in water content and air foam content. It was also found that the modulus of deformation E50 was in a range of 44 to 128 times greater than the value of uniaxial compressive strength, cured in 28 days.

• 소성∙가공
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• 제23권4호
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• pp.231-237
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• 2014

In the current study, a rate-dependent crystal plasticity finite element method (CPFEM) was used to simulate flow stress behavior and texture evolution of a body-centered cubic (BCC) crystalline material during plastic deformation at room temperature. To account for crystallographic slip and rotation, a rate-dependent crystal constitutive law with a hardening model was incorporated into an in-house finite element program, CAMPform3D. Microstructural heterogeneity and anisotropy were handled by assigning a crystallographic orientation to each integration point of the element and determining the stiffness matrix of the individual crystal. Uniaxial tensile tests of single crystals with different crystallographic orientations were simulated to determine the material parameters in the hardening model. The texture evolution during four different deformation modes - uniaxial tension, uniaxial compression, channel die compression, and simple shear deformation - was investigated based on the comparison with experimental data available in the literature.

• 대한기계학회논문집
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• 제11권6호
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• pp.975-981
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• 1987

본 연구에서는 제안된 특수 구성방정식으로 부터 얻은 이론치는 Shipman등에 의해 얻어진 정수압 압축및 1축 변형율 압축상태 하의 다공질 텅스텐의 실험치와 비교 하여 아주 잘 일치하였다.

• Steel and Composite Structures
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• 제21권1호
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• pp.37-55
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• 2016

In this study, the influence of centrally placed circular and square cutouts on vibration and buckling characteristics of different ply-oriented laminated panels under the action of compressive and/or tensile types of non-uniform in-plane edge loads are investigated. The panels are inspected under the action of uniaxial compression, uniaxial tension and biaxial, compression-tension, loading configurations. Furthermore, the effects of different degrees of edge restraints and panel aspect ratios are also addressed in this work. Towards this, a nine-node heterosis plate element has been adopted which includes the effect of shear deformation and rotary inertia. According to the results, the tensile buckling loads are higher than that of compressive buckling loads. However, the tensile buckling load continuously reduces with the increased cutout sizes irrespective of ply-orientations. This is also true for compressive buckling loads except for some particular ply-orientations with higher sized cutouts.

• 한국안전학회지
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• 제18권1호
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• pp.89-93
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• 2003

The failure of rock slopes were influenced by weathering, which causes change in the shear strength. The weathering is also directly related to slaking and swelling characteristics. In the paper, the core of diameter loom was obtained by digging on rock slope of Kong-ju in Korea and then EDX(Energy Dispersive X-ray spectrometer) analysis was carried out to verified element of chief rock-forming minerals. Uniaxial compression tests, slaking tests, and point load test are performed to study engineering characteristics of conglomerate and red shale. As a results of slaking test, slaking index of conglomerate indicate range of 85.11-99.58 and shale indicate 58.37-99.23. Therefore, it is recognized that the resistance of shale to weathering decreases in shallow depth and it greatly influences the strength of rock. The result of uniaxial compression test and Point load test show that the strength of sedimentary such as conglomerate and red shale has an influence on both weathering and saturation.

• Geomechanics and Engineering
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• 제12권4호
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• pp.627-637
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• 2017

The high positive correlation between plastic strain of loaded coal-rock and AE (acoustic emission) characteristic parameter was studied and proved through AE experiment during coal-rock uniaxial compression process. The results show that plastic strain in the whole process of uniaxial compression can be gained through the experiment. Moreover, coal-rock loaded process can be divided into four phases through analyzing the change of the plastic strain curve : pressure consolidation phase, apparent linear elastic phase, accelerated deformation phase, rupture and development phase, which corresponds to conventional elastic-plastic change law of loaded coal-rock. The theoretical curve of damage constitutive model is in high agreement with the experimental curve. So the damage evolution law of coal rock damage can be indicated by both acoustic emission and plastic strain. The results have great academic and realistic significance for further study of both AE signal characteristics during loaded coal-rock damaged process and the forecasting of coal-rock dynamic disasters.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.27-28
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• 2009

건축물의 지진모의실험을 수행할 경우, 부재에 작용하는 전단력과 축력의 계측이 필요하다. 본 연구에서는 2축 전단, 1축 압축을 측정할 수 있는 Load Cell의 제작 및 Calibration법을 제시하고 있다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.327-333
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• 2004

Corestone ground mass has complicated characteristics as it is made up of hard and stiff corestone in a relatively weak and soft matrix. Model corestone ground mass which is physically identical with the stiff corestone in weak matrix were tested in uniaxial compression. The tests show that the increase of the corestone proportion brought the gradual increase of the elastic modulus as well. The ground mass was weaker when the corestone proportion was low while it was stronger in higher corestone proportion. The size of the corestone had no influence on the strength and elastic modulus as long as the proportion of the corestone remains same.

• Computers and Concrete
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• 제1권4호
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• pp.433-455
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• 2004

The paper presents results of FE-calculations on shear localizations in quasi-brittle materials during both an uniaxial plane strain compression and uniaxial plane strain extension. An elasto-plastic model with a linear Drucker-Prager type criterion using isotropic hardening and softening and non-associated flow rule was used. A non-local extension was applied in a softening regime to capture realistically shear localization and to obtain a well-posed boundary value problem. A characteristic length was incorporated via a weighting function. Attention was focused on the effect of mesh size, mesh alignment, non-local parameter and imperfections on the thickness and inclination of shear localization. Different methods to calculate plastic strain rates were carefully discussed.