• Structural Engineering and Mechanics
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• v.56 no.3
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• pp.355-367
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• 2015

This paper deals with a new designed joint system for single-layer spatial structures. As the stability of these structures is greatly influenced by the joint behaviour, the aim of this paper is the characterization of the joint response in bending through Finite Element Method (FEM) analysis using ABAQUS. The behaviour of the joints studied here was influenced by many geometrical factors, such as bolts and plate sizes, distance between bolts and end-plate thickness. The study comprised five models of joints with different values of those parameters. The numerical results were compared to the results of previous experimental tests and the agreement was good enough. The differences between the numerical and experimental initial stiffness are attributed to the simplifications introduced when modelling the bolt threads as well as the presence of residual stresses in the test specimens.

• Journal of Korean Neurosurgical Society
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• v.37 no.5
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• pp.364-369
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• 2005

Objective: Spinal instrumentation without fusion often fails due to biological failure of intervertebral joints (spontaneous fusion, degeneration, etc). The purpose of this study is to investigate the influence of fixation rigidity on viability of intervertebral joints. Methods: Twenty pigs in growing period were subjected to posterior segmental fixation. Twelve were fixed with a rigid fixation system(RF) while eight were fixed with a flexible unconstrained implant(FF). At the time of the surgery, a scoliosis was created to monitor fixation adequacy. The pigs were subjected to periodic radiological examinations and 12pigs (six in RF, six in FF) were euthanized at 12-18months postoperatively for analysis. Results: The initial scoliotic curve was reduced from $31{\pm}5^{\circ}$ to $27{\pm}8^{\circ}$ in RF group (p=0.37) and from $19{\pm}4^{\circ}$ to $17{\pm}5^{\circ}$ in FF group (p=0.21). Although severe disc degeneration and spontaneous fusion of facet joints were observed in RF group, disc heights of FF group were well maintained without major signs of degeneration. Conclusion: The viability of the intervertebral joints depends on motion spinal fixation. Systems allowing intervertebral micromotion may preserve the viability of intervertebral discs and the facet joint articular cartilages while maintaining a reasonably stable fixation.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.05a
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• pp.53-62
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• 2004

A single layer latticed dome is one of the most efficient structures because of its low specivic gravity. For easily analyzing of a single layer latticed dome, joint system is assumed to be pin or rigid joint. However, its joint uses ball whose system has intermediate properties of pin and rigid joint. Therefore this study has a grasp of bending rigidity, stress and mechanical properties through experimental and analyzing method of the bolt inserted ball joint. To analyze the stress of bolt and sleeve, this study uses through 3D elastic contact and cubic element, and then the ball and the bolt are perfectly connected for easily analyzing Compared experimental results to F.E.M, each specimen has an error of less than 12 percent. In the results of stress distribution through F.E.M, stress occurs from bottom of bolt to top of sleeve, and most of tension appears on the bolt, also compression occurs from upper parts of the bolt to the sleeve. The assumption of bending stiffness in ball joint is well known that bolt resists only tension and upper sleeve resiss compression. The results of experiment and analysis have $7{\sim}56%$ error, assuring that upper part of bolt occurs of partial compression. In the result of modified assumption have $4{\sim}20%$ error.

• Journal of Welding and Joining
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• v.17 no.6
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• pp.25-31
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• 1999

Stainless steel sheets are commonly used for vehicles such as the bus and the train. These are mainly fabricated by spot-welding. By the way, its fatigue strength is lower than base metal due to high stress concentration at the nugget. edge of the spot-welding. By the way, its fatigue strength is lower than base metal due to high stress concentration at the nugget edge of the spot-welding point. Especially, it is influenced by welding conditions as well as geometrical factors of spot welded joint. Therefore, it is not too much to say that structural rigidity and strength of spot-welded structures is decided by fatigue strength of spot welded lap joint. Thus, it is necessary to establish a reasonable and systematic long life design criterion for the spot-welded structure. In this study, numerical stress analysis was performed by using 3-dimensional finite element model on IB-type spot-welded lap joint of 304 stainless steel sheet under tension-shear load. Fatigue tests were also conducted on them having various thickness, joint angle, lapped length, and width of the plate. From the results, it was found that fatigue strength of IB-type spot-welded lap joints was influenced by its geometrical factors, however, could be systematically rearranged by maximum principal stress ({TEX}$σ_{1max}${/TEX}) at the nugget edge of the spot-welding point.

• Journal of Ocean Engineering and Technology
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• v.9 no.2
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• pp.20-29
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• 1995

When structures are constructed by welding, structural elements are always accompained by welding residual stress and deformation. Therefore, when the rigidity and strength of the welded structures is considered, it is very important to have sufficient information about the effect of initial deflection and welding residual stress on them. In this paper, the square plates with welding residual stress under compression are dealt with; First, heat conduction and thermal elastic-plastic problems are analyzed by finite element method using 4-node isoparametric elements for assessment on the ultimate strength of welding joint. Later, the ultimate strength of welding joint is assessed by examining the effect of changed type of loading. The specimens are 500{\times}$500mm(a/b=1) and 750{\times}$500mm(a/b=1.5) rectangular plates of whichthicknesses is 9.0mm and simply supported plates getting axiul load in each direction.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.234-238
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• 1999

This study suggests the design of the functionally gradient composite, [0/90/0/core]$_s$ cross-ply laminate, to prevent stress concentration induced from the difference of rigidity between the bone and the artificial hip joint and to reinforce the wear property of the surface and the expectation of their mechanical properties. First, the four-point bending test is done about wet bones and dry bones to know the mechanical properties of the cortical bones. In result, the wet bone shows the viscoelastic behavior and the dry bone shows the elastic behavior. Moreover, we expect the properties of the proposed gradient composites as a function of carbon fiber volume fraction in each layer to apply Halpin-Tsai equation, CLPT(classical laminate plate theory), and Bernoulli beam theory etc. and decide the thickness ratio of each lamina in order to match Young's modulus of the anisotropic cortical bone with the proposed gradient composites.

• Steel and Composite Structures
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• v.19 no.3
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• pp.547-567
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• 2015

The paper makes the experimental and finite-element-analysis investigation on the seismic behavior of the rebar-penetrated joint between gangue concrete filled steel tubular column and reinforced gangue concrete beam under low cyclic reversed loading. Two specimens are designed and conducted for the experiment to study the seismic behavior of the rebar-penetrated joint under cyclic loading. Then, finite element analysis models of the rebar-penetrated joint are developed using ABAQUS 6.10 to serve as the complement of the experiment and further analyze the seismic behavior of the rebar-penetrated joint. Finite element analysis models are also verified by the experimental results. Finally, the hysteretic performance, the bearing capacity, the strength degradation, the rigidity degradation, the ductility and the energy dissipation of the rebar-penetrated joint are evaluated in detail to investigate the seismic behavior of the rebar-penetrated joint through experimental results and finite element analysis results. The research demonstrates that the rebar-penetrated joint between gangue concrete filled steel tubular column and reinforced gangue concrete beam, with full and spindle-shaped load-displacement hysteretic curves, shows generally the high ductility and the outstanding energy-dissipation capacity. As a result, the rebar-penetrated joint exhibits the excellent seismic performance and meets the earthquake-resistant requirements of the codes in China. The research provides some references and suggestions for the application of the rebar-penetrated joint in the projects.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.8-14
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• 2019

In Korean traditional wooden architecture, joint performance varies with the material characteristics of timber, the form of joint, the precision of timber-trimming and the like. Case studies prove that the beam-to-column joint type has large influence on the degrees of deformation and spacing. This is not only true of single-story buildings, but also of large-scale multi-story buildings more apparently. Therefore, this study followed the process of examining to joint types, producing their specimens and testing their structural performance. As a consequence of structural test, the dovetail joint specimen showed the best outcomes of the maximum load and rigidity. Synthesizing the structural performances by respective forms of joints, the Doraegeoji dovetail joint specimen showed the higher performance, followed in order by the Doraegeoji mortise joint specimen and the Tongneoko dovetail joint specimen. The structural performance of a building varies with the characteristics by the shouldering forms of penetrating beams and with the joint types within the columns. This should be considered for the new construction or restoration of multi-story buildings, and be continuously researched henceforth.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.32 no.1
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• pp.1-5
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• 2019

In this paper, the experimental study and finite elements analysis were conducted on homogeneous and dissimilar metals single lap-shear bonded joints to investigate the factor that affect the joint failure load. It was found that factors which have the significant effects on the failure load of the joint was stiffness of the adherends. And from experimental results, it can be confirmed that the failure load increases linearly with overlap length increases. And the failure load of dissimilar metal joints is approximately 1KN(10~17%) larger than homogeneous metal joints. In order to confirm this phenomenon, the stress distribution and strain distribution of the specimens were analyzed through the finite element analysis. The difference between homogeneous metals joints and dissimilar metals joints is that stress and strain in adhesive are concentrated at the end of the overlap zone close to aluminium which has lower rigidity than aluminium in case of dissimilar metals joints. From high rigidity of steel, the stress concentration in bonds are decreased and it cause increase of the failure strength at dissimilar metal joints.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.1117-1120
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• 1999

In this paper, we design the H$\infty$ optimal controller satisfying robust stability and performance in spite of the plant uncertainty for an electro-mechanical actuator system and analyze the controller in frequency domain. H$\infty$ optimal controller K was designed using iteration algorithm suggested by DOYLE. Using the controller in an electro-mechanical actuator system, the joint with very small coupling rigidity coefficient was used to vary the control parameter. The plant unstructured uncertainty was assumed to be a multiplicative type.