• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.2
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• pp.413-423
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• 1991

Multiaxial loading by combinations of tension-torsion-internal pressure have been applied to the thins-walled tubular specimens prepared from cold drawn tubes of SAE 1020 steel. Prior to the multiaxial loading, each specimen has been twisted to different shear strains. Uniaxial tensile yield stresses measured at different angles to the tube axis clearly show that the initial orthotropic symmetry is maintained during twisting. The orthotropy axes are observed to rotate with shear strains. The plane stress yield locus measured for each twisted specimens show that yield surface shape does not remain similar during twisting and thus anisotropic work hardening is not a function of only plastic work.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.3-4
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• 2009

This study predicts the structural behavior of RC beams using high strength shear reinforcement and evaluates current design codes restricting the strength of shear reinforcement steel. Under the present design codes, the yield strength of shear reinforcement steel is restricted to 400MPa. In case that use high yield strength reinforcement steel, could incure heavily crack and deflection at the members of structure, and have not verified ductility capacity, fatigue resisting capacity, shear and torsion resisting capacity, anchoring capacity and seismic capacity. To this end, we evaluate structural behavior of reinforced concrete beams using high strength shear reinforcement.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.342-342
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• 1994

(1) 바셀린은 30 $^{\circ}C$ 이하에서는 항복치를 갖는 의소성 유동거동을 나타내며 이때의 유동특성은 Herschel-Bulkley의 유동모델과 일치한다. (2) 30-50 $^{\circ}C$ 범위에서는 Bingham 모델에 따른 이상 소성 유동 거동을 나타낸다. (3) 50 $^{\circ}C$ 이상의 고온에서는 항복치를 갖지 않는 순수한 Newton 점성유체로 간주할 수 있다. (4) 바셀린의 유동곡선은 전단속도의 단계적 증감에 따라 비가역적인 히스테리시스 루프를 그리나 루프의 면적은 온도 증가에 따라 감소한다. (5) 큰 전단속도로부터 급격히 낮은 전단속도를 부가하면 응력의 평형치에 도달할 때까지 상당한 시간을 필요로 한다. (6) 40 $^{\circ}C$ 이상 온도에서의 유동거동은 시간에 무관하다.

• Journal of the Korea Concrete Institute
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• v.14 no.1
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• pp.110-117
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• 2002

In a strengthened bridge deck which received increased service loads, failure patterns of bridge deck vary depending on deck thickness, compressive strength of concrete, yielding strength of reinforcement, reinforcement ratio and additional strengthening ratio. General failure pattern that is most commonly reported as punching shear failure after the main rebar yields, followed by yielding of distributing rebar. In this paper, by Proposing a limit to the amount of strengthening material, a brittle failure can be prevented and a ductile failure mode similar to that developed in unstrengthened deck is derived. In order to calculated the limit strengthening ratio, the yield line theory and previously proposed plastic punching shear model have been used

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.12
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• pp.285-291
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• 2016

The purpose of this study was to evaluate the structural capacity of steel pipe pile specimens reinforced with hollow steel plate shear connectors by pull-out test. Compressive strength testing of concrete was conducted and yield forces, tensile strengths and elongation ratios of re-bars and hollow steel plate were investigated. A 2,000kN capacity UTM was used for the pull-out test with 0.01mm/sec velocity by displacement control method. Strain gauges were installed at the center of re-bars and hollow steel plates and LVDTs were also installed to measure the relative displacement between the loading plate and in-filled concrete pile specimens. The yield forces of the steel pipe pile specimens reinforced with hollow steel plate shear connectors were increased 1.44-fold and 1.53-fold compared to that of a control specimen, respectively. Limited state forces of steel pipe pile specimens reinforced with hollow steel plate shear connectors were increased 1.23-fold and 1.29-fold compared to that of a control specimen, respectively. Yield state displacement and limited state displacement of steel pipe pile specimens reinforced with hollow steel plate shear connector were decreased 0.61-fold and 0.42-fold compared to that of a control specimen, respectively.

• The Korean Journal of Rheology
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• v.10 no.3
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• pp.165-172
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• 1998

본논문에서는 전기장 부하에 따라 유동성질이 변화하는 ER유체의 빙햄특성을 실험 적으로 연구하였다. 특히 ER유체의 빙행특성에 영향을 주는 여러인자중 전극 간격 및 재질 에 따른 ER유체의 항복전단응력과 전류밀도의 변화를 온도에 따라 고찰하였다. 이를 위하 여 전극 간격을 가변시킬수 있는 전기 점도계를 세가지 재질로 자체 제작하였다. 전극간격 은 0.75 mm, 1.00mm 및 1.25 mm 로 설정하였으며 전극 재질은 스테인레스 스텔, 동 그리 고 기계구조용 탄소강(SMS45C)을 사용했다. 한편 실험에 사용된 ER유체는 자체 조성한 수 계 ER유체인 ERF-1과 외국의 우수하다고 알려진 비수계 ER유체인 ERF-2 두가지를 선택 하였다. 실험은 $25^{\circ}C$와 7$0^{\circ}C$ 및 10$0^{\circ}C$에서 수행하였으며 전기장은 0-4kV/mm 범위에서 온 도 및 ER유체의 종류에 따라 부하 가능한 전압까지 공급하였다. 전단변형률 50, 100, 150, 200, 400, 600, 800, 1000 및 1200 s-1에서 얻은 전단응력 실험결과로부터 최소오차선형법을 이용하여 전단변형률 영에서 동적 항복전단응력 값을 도출하였으며 그결과로부터 전극 간격 및 재질에 따른 ER효과의 변화를 고찰하였다. 또한 상온과 10$0^{\circ}C$에서 4kV/mm의 전기장을 부하하여 전기장에대한 ER유체의 응답특성을 실험을 수행했다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.4
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• pp.1227-1240
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• 2014

Abandoned mines often cause environmental problems, such as alteration of landscape, metal contamination, and landslides due to a heavy rainfall. Geotechnical and rheological tests were performed on waste materials corrected from Imgi waste rock dump, located in Busan Metropolitan City. Debris flow mobility was examined with the help of 1-D BING model which was often simulated in both subaerial and subaqueous environments. To determine flow curve, we used a vane-penetrated rheometer. The shear stress (${\tau}$)-shear rate (${\dot{\gamma}}$) and viscosity(${\eta}$)-shear rate (${\dot{\gamma}}$) relationships were plotted using a shear stress control mode. Well-known rheological models, such as Bingham, bilinear, Herschel-Bulkley, Power-law, and Papanastasiou concepts, were compared to the rheological data. From the test results, we found that the tested waste materials exhibited a typical shear shinning behavior in ${\tau}$-${\dot{\gamma}}$ and and ${\eta}$-${\dot{\gamma}}$ plots, but the Bingham behavior is often observed when the water contents increased. The test results show that experimental data are in good agreement with rheological models in the post-failure stage during shearing. Based on the rheological properties (i.e., Bingham yield stress and viscosity as a function of the volumetric concentration of sediment) of waste materials, initial flowing shape (5 m, 10 m, and 15 m) and yield stress (100 Pa, 200 Pa, 300 Pa, and 500 Pa) were input to simulate the debris flow motion. As a result, the runout distance and front velocity of debris flow are in inverse propositional to yield stress. In particular, when the yield stress is less than 500 Pa, most of failed masses can flow into the stream, resulting in a water contamination.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.4
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• pp.67-76
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• 2014

In this study, the behavior of Steel Plate Concrete (SC) walls subjected to shear and axial forces to investigate the effects of shape and arrangement spacing of studs on the design of SC walls was analytically reviewed. For this purpose, 9 cases of finite element analyses considering the different shape and spacing of studs in SC wall were performed. The results showed that the steel plate was yielded at the lower load than the second yielding shear force of the design skeleton curve when the spacing of stud is excessively far from each other. It is also found that the shape of the stud did not affect the shear behavior of SC wall but, the spacing influenced to its composite action. In this study, it was also proven that the inclined shaped stud resists more effectively to the bucking load than the general shaped stud in SC wall.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.520-525
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• 1997

액체금속로의 안전성과 경제성을 향상시키는데 중요한 요소로 부각된 면진설계기술을 개발하기 위하여 고감쇠 면진베어링의 축소모델을 제작하고, 성능확인을 위한 다양한 시험을 실시하였다. 면진베어링의 성능을 나타내는 전단강성, 감쇠특성, 항복하중특성값, 전단변형능력 등에 대한 시험결과 전단강성은 목표값에 비하여 작았지만 감쇠값과 전단변형은 목표값에 근접하였다. 이를 이용한 면진 원자로건물의 지진응답을 분석한 결과 면진베어링은 건물의 지진응답 가속도를 대폭 줄여주는 것으로 나타났다.

• Korean Journal of Food Science and Technology
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• v.32 no.4
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• pp.974-978
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• 2000

The vane method was used to measure yield stresses of five commercial kochujang samples under a controlled shear-rate operating condition. Magnitudes of vane yield stress were higher than those of yield stress using Casson model with a concentric cylinder viscometer. Magnitudes of vane yield stresses showed great differences between the static $({\sigma}_s)$ and dynamic yield stresses $({\sigma}_d)$ of kochujang samples with undisturbed structure (UDS) and with broken down structure (BDS). A dimensionless yield number $(N{\sigma}_o)$ was determined from the ratio of ${\sigma}s$ to ${\sigma}d$ in order to describe the existence of temporary structure of kochujang.