• 한국공간구조학회:학술대회논문집
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• 한국공간구조학회 2006년도 춘계 학술발표회 논문집 제3권1호(통권3호)
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• pp.182-188
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• 2006

This study propose cutting body portion-high strength bolts to improve deformation capacity of High strength bolts, which are the mechanical fasteners used for End-plate connection. And, we report that loading test results of steel beam-to-column connection using high deformation capacity-high strength bolts in accordance with SAC2000 loading program. As a result, the initial stiffness and the maximum strength of the connection using high deformation capacity-high strength bolts, are approximately the same in comparison with those of the end-plate connection using the existing high strength bolts. But the deformation capacity of the connection is more than twice as much as those.

• 한국공간구조학회논문집
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• 제6권3호
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• pp.123-130
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• 2006

본 연구에서는 기존의 고력볼트의 축부절삭 가공방법을 이용한 신형상 메카니컬패스너를 개발하였다. 개발된 신형상 메카니컬패스너를 엔드플레이트 형식의 보-기둥 접합부에 적용하여 변형능력 및 강도특성에 대한 재하실험 및 유한요소법에 의한 수치해석을 수행하였다.

• 열처리공학회지
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• 제15권6호
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• pp.272-278
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• 2002

The changes in damping capacity with volume fractions of thermal and deformation-induced ${\varepsilon}$ martensites were compared and analyzed in an Fe-23%-Mn alloy. The volume fraction of thermal ${\varepsilon}$ martensite increased with decreasing cooling temperature, whereas that of deformation-induced ${\varepsilon}$ martensite increased steeply up to 10%- of cold rolling and nearly saturated in further cold rolling. In the case of thermal ${\varepsilon}$ martensite, the damping capacity increased linearly with the increase in ${\varepsilon}$ martensite content. For the deformation-induced ${\varepsilon}$ martensite, however, the damping capacity increased continuously up to 70%- of ${\varepsilon}$ martensite, over which it decreased suddenly. TEM microstructures showed that the deterioration of damping capacity above 70%- of deformation-induced ${\varepsilon}$ martensite is ascribed to the introduction of perfect dislocations, which play a important role in inhibiting the movement of damping sources such as stacking fault boundaries inside ${\varepsilon}$ martensite, ${\varepsilon}$ martensite variant boundaries and ${\gamma}/{\varepsilon}$ interfaces.

• 한국재료학회지
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• 제24권1호
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• pp.1-5
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• 2014

This study is experimentally investigated whether or not a relationship exists between the mechanical properties and damping capacity of cold-rolled 316 L stainless steel. Deformation-induced martensite was formed with surface relief and directionality. With the increasing degree of deformation, the volume fraction of ${\varepsilon}$-martensite increased, and then decreased, while ${\alpha}^{\prime}$-martensite increased rapidly. With an increasing degree of deformation, tensile strength was increased, and elongation was decreased; however, damping capacity was increased, and then decreased. Tensile strength and elongation were affected in the ${\alpha}^{\prime}$-martensite; hence, damping capacity was influenced greatly by ${\varepsilon}$-martensite. Thus, there was no proportional relationship between strength, elongation, and damping capacity.

• 한국공간구조학회논문집
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• 제21권3호
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• pp.61-68
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• 2021

In this study, a rocking behavior experiment using a guide plate and a guide channel to prevent lateral deformation of a steel damper was planned. For this purpose, strut I-type specimen I-1 and strut S-type specimen S-1 were prepared. The experimental results were compared with the existing experimental results of SI-260 and SS-260 under the same conditions without the details of lateral deformation prevention in order to evaluate the effect of preventing lateral deformation. The damper with lateral deformation prevention detail was evaluated to have superior strength capacity, deformation capacity, and energy dissipation capacity than the damper without it. Therefore, the lateral deformation prevention detail was evaluated to have a good effect in improving the design capability of the steel damper.

• 한국재료학회지
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• 제29권3호
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• pp.160-166
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• 2019

This study investigates the effect of thermo-mechanical treatment on the damping capacity of the Fe-20Mn-12Cr-3Ni-3Si alloy with deformation induced martensite transformation. Dislocation, ${\alpha}^{\prime}$ and ${\varepsilon}-martensite$ are formed, and the grain size is refined by deformation and thermo-mechanical treatment. With an increasing number cycles in the thermo-mechanical treatment, the volume fraction of ${\varepsilon}-martensite$ increases and then decreases, whereas dislocation and ${\alpha}^{\prime}-martensite$ increases, and the grain size is refined. In thermo-mechanical treated specimens with five cycles, more than 10 % of the volume fraction of ${\varepsilon}-martensite$ and less than 3 % of the volume fraction of ${\alpha}^{\prime}-martensite$ are attained. Damping capacity decreases by thermo-mechanical treatment and with an increasing number of cycles of thermo-mechanical treatment, and this result shows an opposite tendency for general metal with deformation induced martensite transformation. The damping capacity of the thermo-mechanical treated damping alloy with deformation induced martensite transformation greatly affect the formation of dislocation, grain refining and ${\alpha}^{\prime}-martensite$ and then ${\varepsilon}-martensite$ formation by thermo-mechanical treatment.

• 한국재료학회지
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• 제25권1호
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• pp.9-15
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• 2015

The effect of retained and reversed austenite on the damping capacity in high manganese stainless steel with two phases of martensite and austenite was studied. The two phase structure of martensite and retained austenite was obtained by deformation for various degrees of deformation, and a two phase structure of martensite and reverse austenite was obtained by reverse annealing treatment for various temperatures after 70 % cold rolling. With the increase in the degree of deformation, the retained austenite and damping capacity rapidly decreased, with an increase in the reverse annealing temperature, the reversed austenite and damping capacity rapidly increased. With the volume fraction of the retained and reverse austenite, the damping capacity increased rapidly. At same volume of retained and reversed austenite, the damping capacity of the reversed austenite was higher than the retained austenite. Thus, the damping capacity was affected greatly by the reversed austenite.

• 한국구조물진단유지관리공학회 논문집
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• 제7권4호
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• pp.225-233
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• 2003

최근 성능에 근거한 설계법의 개발과 더불어, 변위설계에 대한 관심이 증가하고 있다. 본 연구에서는 다층 RC 골조의 변위성능을 보다 정확하게 평가할 수 있는 방법을 제시하고자 한다. 이를 위해, 골조의 횡변위를 계산하기 위해서 보와 기둥의 변형뿐만 아니라 정착부와 조인트 부분의 변형을 변위 산정시 고려하였다. 기존의 실험 및 계산결과의 비교로부터, 본 연구에서 제시한 방법의 적합성을 확인하였고, 이를 강한 기둥-약한 보의 설계개념을 설계된 다층 RC골조 건물에 적용하여 그 거동을 예측하였다. 그 결과, 보다 정확한 건물의 변위성능을 평가하기 위해서는 정착부와 조인트의 변형을 반드시 반영하여야 하는 것으로 나타났다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 봄 학술발표회 논문집
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• pp.512-519
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• 2000

The discharge capacity of vertical drains installed in the field is reduced with time elapsed after installation due to deformation of drains and clogging effect. Discharge capacity of two types of vertical drains was analysed about three years after installation in the subsoil. Discharge capacity of two types of vertical drains were measured by small, middle, and large scale test apparatus. The results indicate that the discharge capacity of vertical drains after three years operation dramatically decreased compare to the initial discharge capacity.

• Computers and Concrete
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• 제18권6호
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• pp.1153-1173
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• 2016

According to deformation data measured in some high concrete dams, for dam body deformation, there is a complex relationship with dam height and water head for different projects, instead of a simple monotonic relationship consistently. Meanwhile, settlement data of some large reservoirs exhibit a significant deformation of reservoir basin. As water conservancy project with high concrete dam and large storage capacity increase rapidly these decades, reservoir basin deformation problem has gradually gained engineers' attentions. In this paper, based on conventional analytical method, an improved analytical method for high concrete dam is proposed including the effect of reservoir basin deformation. Though establishing FEM models of two different scales covering reservoir basin and near dam area respectively, influence of reservoir basin on dam body is simulated. Then, forward and inverse analyses of concrete dam are separately conducted with conventional and proposed analytical methods. And the influence of reservoir basin deformation on dam working behavior is evaluated. The results of two typical projects demonstrate that reservoir basin deformation will affect dam deformation and stress to a certain extent. And for project with large and centralized water capacity ahead of dam site, the effect is more significant than those with a slim-type reservoir. As a result, influence of reservoir basin should be taken into consideration with conducting analysis of high concrete dam with large storage capacity.