• Structural Engineering and Mechanics
• /
• 제7권1호
• /
• pp.95-110
• /
• 1999

An effective moment of inertia is developed for a rectangular, prismatic elastoplastic beam with elastic, linear-hardening material behavior. The particular solution for a beam with elastic, perfectly plastic material behavior is also presented with applications for beam bending in closed-form. Equations are presented for the direct application of the virtual work method for elastoplastic beams with concentrated and distributed loads. Comparisons are made between the virtual work method deflections and the deflections obtained by using an average effective moment of inertia over two lengths of the beam in the elastoplastic region.

• Steel and Composite Structures
• /
• 제15권3호
• /
• pp.299-322
• /
• 2013

In the case of seismic-resistant composite dual moment resisting and eccentrically braced frames, the current design practice is to avoid the disposition of shear connectors in the expected plastic zones, and consequently to consider a symmetric moment or shear plastic hinges, which occur only in the steel beam or link. Even without connectors, the real behaviour of the hinge may be different from the symmetric assumption, since the reinforced concrete slab is connected to the steel element close to the hinge locations, and also due to contact friction between the concrete slab and the steel element. The paper presents the results and conclusions of experimental tests on composite portal eccentrically braced frames and beam-to-column moment-resisting joints, carried out within the CEMSIG Research Centre of the Politehnica University of Timisoara, in order to check the validity of the assumption stated above. Reference steel and composite specimens with and without connectors in the plastic zones have been tested under monotonic and cyclic seismic type loading.

• Steel and Composite Structures
• /
• 제15권3호
• /
• pp.323-342
• /
• 2013

In the case of seismic-resistant composite dual moment resisting and eccentrically braced frames, the current design practice is to avoid the disposition of shear connectors in the expected plastic zones, and consequently to consider a symmetric moment or shear plastic hinges, which occur only in the steel beam or link. Even without connectors, the real behavior of the hinge may be different from the symmetric assumption since the reinforced concrete slab is connected to the steel element close to the hinge locations, and also due to contact friction between the concrete slab and the steel element. At a larger level, the structural response in the case of important seismic motions depends directly on the elasto-plastic behavior of elements and hinges. The numerical investigation presented in this study summarizes the results of elasto-plastic analyses of several steel frames, considering the interaction of the steel beam with the concrete slab. Several parameters, such as the inter-story drift, plastic rotation requirements and behavior factors q were monitored. In order to obtain accurate results, adequate models of plastic hinges are proposed for both the composite short link and composite reduced beam sections.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2005년도 추계학술대회 논문집
• /
• pp.448-451
• /
• 2005

It was observed that after unloading or removal of the load from the specimen subjected to bending stress, partial or full elastic spring back occurred and considerable stresses have resulted while plastic deformation was considered. ABAQUS is a suite of powerful engineering simulation programs, based on the finite element method. In this paper, it was used as the main tool to analyze elastic and plastic deformations of hi-material metal joint. In the case of elastic deformations, the results were comparable to the theoretical data. Plastic deformations and residual stresses of hi-material metal joint under bending moment were obtained by ABAQUS; where the theory needs to be studied and improved further to verify the results.

• Structural Engineering and Mechanics
• /
• 제7권5호
• /
• pp.513-525
• /
• 1999

This paper presents exact close form solutions of plastic limit loads of a clamped circular plate under uniformly distributed load with different loading radii. A unified yield criterion, which includes a family of piecewise linear yield criteria and the commonly adopted yield criteria such as the Tresca criterion and the maximum principal deviatoric stress criterion or the twin shear stress criterion that are its special cases, and the Mises criterion can be approximated by it, is employed in the analysis. The plastic limit loads, moment fields and velocity fields of the clamped circular plate are calculated based on the unified yield criterion. The influences of the yield criteria, the edge effects and the loading radius on the plastic limits of the clamped circular plate are investigated. Analytical results are calculated and compared. The exact close form solutions presented in this paper provide efficient approaches for obtaining plastic limit loads and the corresponding moments and velocities of the clamped circular plates. The previously derived solutions based on the Tresca and the Mises criteria are its special cases.

• 대한기계학회논문집A
• /
• 제31권4호
• /
• pp.496-505
• /
• 2007

This paper proposes closed-form plastic limit load solutions for elbows under in-plane bending, via three-dimensional (3-D), small strain FE limit analyses using elastic-perfectly plastic materials. A wide range of elbow and thinning geometries are considered. For systematic analyses of the effect of the axial thinning length on limit loads, two limiting cases are considered; a sufficiently long wall thinning, and the circumferential part-through surface crack. Closed-form plastic limit load solutions for wall thinning with intermediate longitudinal extents are then obtained from these two limiting cases. The effect of the axial extent of wall thinning on plastic limit loads for elbows is highlighted by comparing that for straight pipes. Although the proposed solutions are developed for the case when wall thinning exists in the center of elbows, it is also shown that they can be applied to the case when wall thinning exists anywhere within the elbow.

• 한국공간구조학회논문집
• /
• 제20권3호
• /
• pp.27-34
• /
• 2020

This paper examines the seismic performance and structural design of the ceiling bracket-type modular connection. The bracket-type system reduces the cross-sectional area loss of members and combines units using fitting steel plate, and it has been developed to be fit for medium-story and higher-story buildings. In particular, this study conducted the cyclic loading test for the performance of the C-type and L-type brackets, and compared the results. The test results were also compared with the commercial FEA program. In addition, the structural design process for the bracket-type modular connection was presented. The two connections, proposed as a result of the test results, were all found to secure the seismic performance level of the special moment steel frame. In the case of initial stiffness, the L-type bracket connection was found to be great, but in the case of the maximum moment or fully plastic moment, it was different depending on the loading direction.

• 한국강구조학회 논문집
• /
• 제15권3호
• /
• pp.261-269
• /
• 2003

편심브레이스골조의 설계에서 가장 중요한 인자는 링크보의 길이이다. 링크보의 길이에 따라 편심브레이스골조의 거동과 파괴메카니즘이 결정된다. 링크보의 길이가 짧아져 전단력에 의해 소성화되면 중심브레이스골조와 대등한 수평방향강성과 모멘트 연성골조의 연성을 동시에 확보할 수 있다. 또한 링크보의 길이가 길어지게 되면 링크보는 모멘트에 의해 소성화 되어 연성적인 거동을 확보할 수 없게 된다. 근래에 이르러 건축계획적인 측면에서는 링크보의 길이가 길어지는 것이 입면 및 단면계획이 용이하며, 그 필요성이 증대되고 있지만, 모멘트 링크에 대한 기존의 연구가 많이 수행되어 있지 않으며, 이와 관련된 자료가 부족한 실정이다. 본 연구에서는 실험을 통해 다양한 접합디테일을 가진 모멘트링크보의 거동을 규명하고 모멘트링크보의 거동을 개선시킬 수 있는 접합디테일을 제시하고자 한다. 4개의 접합 디테일을 가진 총 16개의 실험체를 계획하여 이력거동 실험을 수행하였다.

• Structural Engineering and Mechanics
• /
• 제21권3호
• /
• pp.295-313
• /
• 2005

This paper evaluates the effective width of composite steel beams with precast hollowcore slabs numerically using the finite element method. A parametric study, carried out on 27 beams with different steel cross sections, hollowcore unit depths and spans, is presented. The effective width of the slab is predicted for both the elastic and plastic ranges. 8-node three-dimensional solid elements are used to model the composite beam components. The material non-linearity of all the components is taken into consideration. The non-linear load-slip characteristics of the headed shear stud connectors are included in the analysis. The moment-deflection behaviour of the composite beams, the ultimate moment capacity and the modes of failure are also presented. Finally, the ultimate moment capacity of the beams evaluated using the present FE analysis was compared with the results calculated using the rigid - plastic method.

• 한국지진공학회:학술대회논문집
• /
• 한국지진공학회 1998년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
• /
• pp.57-64
• /
• 1998

This paper presents the cyclic seismic performance of slip-critically designed, high-strength bolted-beam splice in steel moment frame. Before the moment connection reaching its plastic strength, unexpected premature slippage occurred at the slip-critically designed beam splice during the test. The experimentally observed frictional coefficients were as low as about 50% to 60% of nominal (code) value. Nevertheless, the bearing type behavior mobilized after the slippage transferred the increasing cyclic loads successfully, i.e., the consequence of slippage into bearing was not catastrophic to the connection behavior. The test result seems to indicate that the traditional beam splice design basing upon (bolt-hole deducted) effective flange area criterion may not be sufficient in developing the plastic strength of moment connections under severe earthquake loading. New procedure for achieving slip-critical beam splice design is proposed based on capacity design concept.