• 한국강구조학회 논문집
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• 제14권2호
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• pp.349-356
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• 2002

현재 우리나라 스틸하우스 건설에 사용하는 구조재는 SGC41 강종으로 제작된 보통 C-형강이나 Lip-C-형강이 주를 이루고 있으나 이 분야의 선진국가에서는 좌굴 강도가 높고 시공성이 좋은 고유의 단면 형상을 개발하여 사용하고 있다. 본 연구에서는 정량이면서 강도 및 강성이 높고 다양한 시공상 장점이 있는 고강도 신형상 박판냉간성형단면의 압축부재로서의 구조적인 고동과 성능을 연구하기 위하여 재료실험 및 압축실험을 수행하고 해석치와 비교하여 보았다.

• Steel and Composite Structures
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• 제44권6호
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• pp.899-912
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• 2022

To study the seismic performance of the all-steel buckling-restrained brace (BRB) using the novel soft steel LY315 for core member, a total of three identical BRBs were designed and a series of experimental and numerical studies were conducted. First, monotonic and cyclic loading tests were carried out to obtain the mechanical properties of LY315 steel. In addition, the parameters of the Chaboche model were calibrated based on the test results and then verified using ABAQUS. Second, three BRB specimens were tested under cyclic loads to investigate the seismic performance. The failure modes of all the specimens were identified and discussed. The test results indicate that the BRBs exhibit excellent energy dissipation capacity, good ductility, and excellent low-cycle fatigue performance. Then, a finite element (FE) model was established and verified with the test results. Furthermore, a parametric study was performed to further investigate the effects of gap size, restraining ratio, slenderness ratio of the yielding segment, and material properties of the core member on the load capacity and energy dissipation capacity of BRBs.

• 한국강구조학회 논문집
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• 제12권1호통권44호
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• pp.29-43
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• 2000

본 연구에서는 비탄성 부재들의 좌굴 강도를 결정하기 위한 계산적으로 효율적인 비탄성 좌굴해석 프로그램이 개발되었다. 본 프로그램은 휨 좌굴, 휨-비틂 좌굴 혹은 국부좌굴에 의해 붕괴되는 탄성과 비탄성 부재들의 좌굴 강도 및 형상을 결정할 수 있다. 일축 대칭이나 2축 대칭인 I 형 부재를 해석할 수 있다. 복부판은 판 요소를 이용하여 모델되고, 플랜지는 보 요소로 모델되었다. 재료의 비탄성 응력-변형률 관계를 모사하기 위하여 다선형 등방경화 법칙과 증분이론이 사용되었다. 프로그램은 이론치와 실험값들을 이용하여 입증되었다. 프로그램의 결과는 이론치 및 실험값들과 잘 일치였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1990년도 가을 학술발표회 논문집
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• pp.22-27
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• 1990

Since an eigenvalue problem in structural analysis has been recognized as an important process for the assessment of structural strength, it is usually to be carried out the eigenvalue analysis or buckling analysis of structures when the compression behabiour of the member is dorminant. In general, various variables involved in the eigenvalue problem have also shown their variability. So it is natural to apply the probabilistic analysis into such problem. Since the limit state equation for the eigenvalue analysis or buckling reliability analysis is expressed implicitly in terms of random variables involved, the probabilistic finite element method is combined with the conventional reliability method such as MVFOSM and AFOSM for the determination of probability of failure due to buckling. The accuracy of the results obtained by this method is compared with results from the Monte Carlo simulations. Importance sampling method is specially chosen for overcomming the difficulty in a large simulation number needed for appropriate accurate result. From the results of the case study, it is found that the method developed here has shown good performance for the calculation of probability of buckling failure and could be used for checking the safety of the calculation of probability of buckling failure and could be used for checking the safely of frame structure which might be collapsed by either yielding or buckling.

• Earthquakes and Structures
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• 제16권5호
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• pp.589-599
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• 2019

Conventional buckling restrained braces used in concentrically braced frames are expected to yield in both tension and compression without major degradation of capacity under severe seismic ground motions. One of the weakness points of a standard buckling restrained braced frame is the low post-yield stiffness and thus large residual deformation under moderate to severe ground motions. This phenomenon can be attributed to low post-yield stiffness of core member in a BRB. This paper introduces a multi-core buckling restrained brace. The multi-core term arises from the use of more than one core component with different steel materials, including high-performance steel (HPS-70W) and stainless steel (304L) with high strain hardening properties. Nonlinear dynamic time history analyses were conducted on variety of diagonally braced frames with different heights, in order to compare the seismic performance of regular and multi-core buckling restrained braced frames. The results exhibited that the proposed multi-core buckling restrained braces reduce inter-story and especially residual drift demands in BRBFs. In addition, the results of seismic fragility analysis designated that the probability of exceedance of residual drifts in multi-core buckling restrained braced frames is significantly lower in comparison to standard BRBFs.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2000년도 가을 학술발표회논문집
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• pp.67-74
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• 2000

Recently western countries are now beginning to use ACM (Advanced Composite Material) in the construction industry. Compared with conventional construction materials, ACM possesses many advantages such as light-weight, high-strength, corrosion resistant properties, etc. Among other fabrication process of ACM, pultrusion is one of the promising one for civil infrastructure application. In this paper, the structural characteristics of pultruded glass fiber reinforced composite structural member of angle and tube type were studied. Experiments for compression were performed for those members along with finite element buckling analysis with ABAQUS. The experimental and analytic results were compared each other and they were also compared with predicted values using coded formulae.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1997년도 봄 학술발표회 논문집
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• pp.240-247
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• 1997

Single-layer latticed domes, which ore consisted of slender linear elements, are able to transmit external loads to the structure by in-plane forces, therefore spatial structures can be constructed with the merit of its own lightweight. But, as external load reaches to any critical level at which each member has not material nonlinearity, the single-layer latticed dome shows unstable phenomenon. In particular, pin-connected single-layer latticed domes have much complicate unstable phenomena that are combined with nodal buckling and member buckling. Furthermore, single-layer latticed domes are very sensible to the initial imperfection which occurred inevitably in construction. In this study, we are going to grasp the characteristics of instability for the latticed dome by finite element method considering geometrical nonlinearity.

• 한국공간정보시스템학회:학술대회논문집
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• 한국공간정보시스템학회 2004년도 춘계 학술발표회 논문집 제1권1호(통권1호)
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• pp.131-138
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• 2004

The cable structure is a kind of ductile structural system using the tension cable and compression column as a main element. From mechanical characteristics of the structural material, it is profitable to be subjected to the axial forces than bending moment or shear forces. And we haweto consider the local buckling when it is subjected to compression forces, but tension member can be used until the failure strength. So we can say that the tension member is the most excellent structural member. Cable dome structures are made up of only the tension cable and compression column considering these mechanical efficiency and a kind of structural system. In this system, the compression members are connected by using tension members, not connected directly each other. Also, this system is lightweight and easy to construct. But, the cable dome structural system has a danger of global buckling as external load increases. That is, as the axisymmetric structure is subjected to the axisymmetric load, the unsymmetric deformation mode is happened at some critical point and the capacity of the structure is rapidly lowered by this reason. This phenomenon Is the bifurcation and we have to reflect this in the design process of the large space structures. In this study, We investigated the nonlinear unstable phenomenon of the Geiger, Zetlin and Flower-type cable dome.

• 한국공간구조학회논문집
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• 제18권1호
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• pp.127-134
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• 2018

This study suggests the tangent modulus $E_t$ associated with partially yielded section of steel member under axially compressed. The provisions for column strength does not provide a information about failure mode of structural system. So, designers can not evaluate that a failure comes from member buckling or material yielding. The material of the axially compressed column under inelastic behavior reaches yielding point before the axial force renders the column bent. If axial members yields not by buckling effect but gradually yielding effect of material, the design code should accept related tangent modulus Et which is based on gradual yielding effect of material. This study provides the new effective tangent modulus $E_t$ derived in the case that residual stress is 30 percent and 50 percent of yielding stress respectively. The study considers idealized I section of steel which ignores web and general I section of steel with web respectively and makes conclude that tangent modulus $E_t$ with idealized I section of steel is rational.

• Structural Engineering and Mechanics
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• 제55권3호
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• pp.605-638
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• 2015

It is intended to perform buckling analysis of steel gabled frames with tapered members and flexible connections. The method is based on the exact solutions of the governing differential equations for stability of a gabled frame with I-section elements. Corresponding buckling load and subsequently effective length factor are obtained for practical use. For several popular frames, the influences of the shape factor, taper ratio, span ratio, flexibility of connections and elastic rotational and translational restraints on the critical load, and corresponding equivalent effective length coefficient are studied. Some of the outcomes are compared against available solutions, demonstrating the accuracy, efficiency and capabilities of the presented approach.