• Steel and Composite Structures
• /
• v.33 no.2
• /
• pp.277-298
• /
• 2019

Concrete filled steel tubular (CFST) column joints with composite beams have been widely used as lateral loading resisting elements in civil infrastructure. To better utilize these innovative joints for the application of structural seismic design and analysis, it is of great importance to investigate the dynamic behavior of the joint under cyclic loading. With this aim in mind, a novel phenomenal model has been put forward in this paper, in which a Bouc-Wen hysteresis component is employed to portray the strength and stiffness deterioration phenomenon caused by increment of loading cycle. Then, a modified chicken swarm optimization algorithm was used to estimate the optimal model parameters via solving a global minimum optimization problem. Finally, the experimental data tested from five specimens subjected to cyclic loadings were used to validate the performance of the proposed model. The results effectively demonstrate that the proposed model is an easy and more realistic tool that can be used for the pre-design of CFST column joints with reduced beam section (RBS) composite beams.

• Steel and Composite Structures
• /
• v.43 no.1
• /
• pp.107-116
• /
• 2022

This paper presents results of numerical studies completed on unreinforced and doubler plate reinforced Elliptical Hollow Section (EHS) T-joints subjected to axial compressive loading on the brace member. Non-linear finite element (FE) models were developed using the finite element code, ABAQUS. Available test data in literature was used to validate the FE models. Subsequently, a parametric study was carried out to investigate the effects of various geometrical parameters of main members and reinforcement plates on the ultimate capacity of reinforced EHS T-joints. The parametric study found that the reinforcing plate significantly increases the ultimate capacity of EHS T-joints up to twice the capacity of the corresponding unreinforced joint. The thickness and length of the reinforcing plate have a positive effect on the ultimate capacity of Type 1 joints. This study, however, found that the capacity of Type 1 orientation is not dependent on the brace-to-chord diameter ratio. As for type 2 orientations, the thickness and length of the reinforcement have a minimal effect on the ultimate capacity. A new design method is introduced to predict the capacity of the reinforced EHS T-joints Type 1 and 2 based on the multiple linear regression analyses.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.1
• /
• pp.203-208
• /
• 2002

In order to reduce the booming noise caused by first bending mode of a drive shaft, this paper proposes a simulation program for prediction of the bending mode frequency of any tubular shaft. This program consists of a pre-processor for modeling of geometrical shape of the drive shaft with boundary conditions of various joints, a processor for constructing of global finite element matrices using beam elements and an eigen-solver based on MATLAB program. Using this simulation program, the effective and accurate FE model far a shaft attached to vehicle can be obtained by aid of database for stiffness of each joint. Thus the resonance frequencies and mode shapes of a shaft can be calculated accurately. Because the effect of the resonance on interior noise can be verified, more improved shaft will be proposed at the early stage of design.

• Journal of Ocean Engineering and Technology
• /
• v.3 no.2
• /
• pp.87-100
• /
• 1989

해양구조물의 원통형 조인트에 대한 파괴역학적 피로수명 산출방법이 개발되었다. 개발된 방법을 이용해서 2평면 K형 조인트에 대한 피로수명을 구체적인 파괴역학적 방법으로 산출 하였다. 이 분석을 위해 용접부위 표면균열의 응력확대 계수를 3차원 유한요소법에 의해 계산하였다. 계산된 결과에 의하면 용접부위 표면균열 첨단은 단순한 Mode I형태를 보이지 않고 Mode I, II, III이 복합된 형태임이 입증되었다. 계산된 응력확대 계수를 사용해서 16개의 용접부위균열 성장형태를 일반적인 피로균열 성장법칙을 적용해서 계산하였고, 균열성장의 안정분석을 통해 각 균열의 최종 파괴상태를 파괴해석도면(failure assessment diagram)법을 이용해서 계산하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2006.04a
• /
• pp.655-663
• /
• 2006

Large-scale model tests of welded tubular K-joints were carried out to observe the fatigue behavior of API 2W Gr.50 steel produced by POSCO. The fatigue crack behaviors for various loading conditions were measured and investigated around the critical joint sections. The experimental results have been verified with numerical approaches and also compared with the IIW, DnV RP-C203 and API RP 2A-WSD design curves. The hot spot strss method was applied in the study. The SCF factor for tubular K-joint was also obtained.

• Computers and Concrete
• /
• v.26 no.6
• /
• pp.547-563
• /
• 2020

In this paper, the influence of axial compression ratio on the mechanical properties of new type joints of side span of rectangular concrete-filled steel tubular column-H-type steel beam is studied. Two new types of side-span joints of rectangular concrete-filled steel tubular column-H-type steel beam are designed and quasi-static tests of five new type joints with 1:2 scale reduction ratios are performed. The axial compression ratio of joint JD1 is 0.3, 0.4 and 0.5, and the axial compression ratio of joint JD2 is 0.3 and 0.5. In the joint test, different axial forces were applied to the top of the column according to different axial compression ratios, and low-cyclic reciprocating load was applied on the beam. The stress and strain distribution, beam and column deformation, limit state, failure process, failure mechanism, stiffness degradation, ductile deformation and energy dissipation capacity of the joint were measured and analyzed. The results show that: with the increase of axial compression ratio, the ultimate bearing capacity of the joint decreases slightly, the plastic deformation decreases, and the stiffness and ductility decrease. According to the energy dissipation curve of the specimen, the equivalent damping coefficient also increases with the increase of axial compression ratio in a certain range, indicating that the increase of axial compression ratio can improve the seismic performance of the joint to a certain extent. The finite element method is used to simulate the joint test, and the test results are in good agreement with the simulation results.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.16 no.10
• /
• pp.1841-1852
• /
• 1992

With the wide application of fiber-reinforced composite material in aircraft, space structures and robot arms, the design and manufacture of composite joints have become a very important research area because they are often the weakest areas in composite structures. In this study, the effects of the adhesive thickness, residual thermal stress on the torque capacity of the tubular single lap joints were studied. The torque capacity of the adhesive joints were experimentally determined and found to be inversely proprotional to the adhesive thickness. In order to match the experimental results to the theoretical analyses, the elastic-perfectly plastic material properties of the adhesive were used in the closed form solution. Also, the residual thermal stress of the joints were calculated by the finite element method and it was proved that the residual thermal stress could play an important role in the thick adhesive joints.

• Steel and Composite Structures
• /
• v.34 no.6
• /
• pp.803-818
• /
• 2020

Semi-rigid connections with blind bolts could solve the difficulty that traditional high strength bolts were unavailable to splice a steel/composite beam to a closed section column. However, insufficient investigations have focused on the performance of semi-rigid connection to square concrete filled double-skin steel tubular (CFDST) columns. In this paper, a component model was developed to evaluate the mechanical behavior of semi-rigid composite connections to CFDST columns considering the stiffness and strength of column face in compression and column web in shear which were determined by the load transfer mechanism and superstition method. Then, experimental investigations on blind bolted composite joints to square CFDST columns were conducted to validate the accuracy of the component model. Dominant failure modes of the connections were analyzed and this type of joint behaved semi-rigid manner. More importantly, strain responses of CFDST column web and tubes verified that stiffness and strength of column face in compression and column web in shear significantly affected the connection mechanical behavior owing to the hollow part of the cross-section for CFDST column. The experimental and analytical results showed that the CFDST column to steel-concrete composite beam semi-rigid joints could be employed for the assembled structures in high intensity seismic regions.

• Steel and Composite Structures
• /
• v.20 no.3
• /
• pp.487-500
• /
• 2016

In order to investigate the flexural bearing capacity of panel zone of diaphragm-through joint between concrete filled square steel tubular column and steel beam, four specimens were tested under static tension loads to study the mechanical properties and bearing capacity of diaphragm-through joints with a failure mode of panel zone. Finite element models of these specimens were developed to simulate the test and compare the predicted failure modes, load-displacement curves and bearing capacities with the experimentally observed. It was found that the tensile load from the steel beam flange is mainly shared by the square steel tube and the diaphragm. The diaphragm plastic zone appears along the cross-section lines enclosed by the square steel tube and the influence of steel beam web on the plastic zone of the steel tube is significant and cannot be neglected. Computational models of yield lines on square steel tube and diaphragm are established based on the distribution pattern of the plastic zone, and an analytical method for the evaluation of the bearing capacity of the joint is proposed. The theoretical results and the experimental data are compared and found in good agreement.

• Steel and Composite Structures
• /
• v.32 no.5
• /
• pp.583-594
• /
• 2019

In recent years, composite concrete-filled steel tubular (CFST) members have been widely utilized in framed building structures like beams, columns, and beam-columns since they have significant advantages such as reducing construction time, improving the seismic performance, and possessing high ductility, strength, and energy absorbing capacity. This paper presents a new composite joint - the composite CFST beam-column joint in which the CFST member is used as the beam. The main components of the proposed composite joint are steel H-beams, CFST beams welded with the steel H-column, and a reinforced concrete slab. The steel H-beams and CFST beams are connected with the concrete slab using shear connectors to ensure composite action between them. The structural performance of the proposed composite joint was evaluated through an experimental investigation. A three-dimensional (3D) finite element (FE) model was developed to simulate this composite joint using the ABAQUS/Explicit software, and the accuracy of the FE model was verified with the relevant experimental results. In addition, a number of parametric studies were made to examine the effects of the steel box beam thickness, concrete compressive strength, steel yield strength, and reinforcement ratio in the concrete slab on the proposed joint performance.