• Steel and Composite Structures
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• v.18 no.5
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• pp.1305-1330
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• 2015

The successful application of the component-based approach - widely used to model structural joints - requires knowledge of the mechanical properties of the constitutive joint components, including an appropriate assembly procedure to derive the joint properties. This paper presents a component-method model for a structural joint component that is located in the tension zone of blind-bolted connections to concrete-filled tubular steel profiles. The model relates to the response of blind-bolts with headed anchors under monotonic loading, and the blind-bolt is termed the "Extended Hollo-bolt". Experimental data is used to develop the model, with the data being collected in a manner such that constitutive models were characterised for the principal elements which contribute to the global deformability of the connector. The model, based on a system of spring elements, incorporates pre-load and deformation from various parts of the blind-bolt: (i) the internal bolt elongation; (ii) the connector's expanding sleeves element; and (iii) the connector's mechanical anchorage element. The characteristics of these elements are determined on the basis of piecewise functions, accounting for basic geometrical and mechanical properties such as the strength of the concrete applied to the tube, the connection clamping length, and the size and class of the blind-bolt's internal bolt. An assembly process is then detailed to establish the model for the elastic and inelastic behaviour of the component. Comparisons of model predictions with experimental data show that the proposed model can predict with sufficient accuracy the response of the component. The model furthers the development of a full and detailed design method for an original connection technology.

• Steel and Composite Structures
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• v.20 no.2
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• pp.267-293
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• 2016

It is well known that, in order to accurately predict the behaviour of steel structures a requirement the definition of the mechanical behaviour of beam-to column joints is of primary importance. This goal can be achieved by means of the so-called component method, which, in order to obtain the whole behaviour of connections, provides to break up joints in basic components of deformability and resistance. One of the main joint components used to model bolted connections is the so-called equivalent T-stub in tension, which is normally used to predict the behaviour of bolted plates in bending starting from the behaviour of the single bolt rows. In past decades, significant research efforts have been devoted to the prediction of the behaviour of bolted T-stubs but, to date, no particular attention has been devoted to the characterization of their plastic deformation capacity. To this scope, the work presented in this paper, taking into account the existing technical literature, proposes a new theoretical model for predicting the whole behaviour up to failure of bolted T-stubs under monotonic loading conditions, including some complexities, such as the bolt/plate compatibility requirement and the bolt fracture, which are necessary to accurately evaluate the ultimate displacement. After presenting the advances of the proposed approach, a comparison between theoretical and experimental results is provided in order to verify its accuracy.

• Journal of the Korean Society of Safety
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• v.34 no.5
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• pp.1-6
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• 2019

The mobile elevated work platforms(MEWPs) consist of work platform, extending structure, and car, and it is a facility to move persons to working positions. MEWPs are useful but composed complex pieces of equipments, and accidents are caused by equipment defects. Among them, accidents caused by fracture of the bolts fixing the extension structure and the turntable are increasing. In this study, fatigue failure and fatigue life of a turntable fixing bolt subjected to irregular fatigue load were analyzed by FEA. For this purpose, finite element modeling is proposed and structural analysis and fatigue analysis are performed simultaneously for fixing bolts. As a result of the structural analysis, it was confirmed that there is no risk of permanent deformation because the maximum stress acting on the fixing bolt is lower than the yield strength, and fatigue analysis was confirmed that the fatigue life is less than the design standard. The fatigue analysis results of this study can be effectively used for the design and the documentary assessment of the safety certification of the MEWPs by examining the fatigue life of the turntable fixing bolt.

• Journal of Korean Society of Steel Construction
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• v.20 no.2
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• pp.279-288
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• 2008

In this study, the slip behavior of high-tension bolted joints subjected to compression force is investigated through 3D finite element analysis and experiments. The relation with sliding load, bolt deformation, and failure load are studied with the metal thickness affecting the bolted joint. The post-sliding behavior considering bolt stiffness is presented and compared with the results by finite element and experiments. The finite element model is constructed by solid elements in ABAQUS, in consideration of all the friction effects between metal plates and bolts. The stress-strain relations in the literature are used, and the sliding displacements and axial stresses around the bolt connection are investigated. The flexural buckling of species happened when the plate thickness is less than the bolt diameter. However, the shear failures of bolt occurred in the opposite case.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.635-636
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• 2008

• Tunnel and Underground Space
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• v.28 no.2
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• pp.142-155
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• 2018

The ${\bigcirc}{\bigcirc}$ mine has irregularly developed stratum around the ore body. The purpose of this study is to array irregular stratum thickness systematically for effective roof bolting and to implement a supporting system corresponding to it. The number of 81 cases combined with stratum thicknesses was limited to 9 cases by robust design. For each case, the load height which can act as a roof load was determined by the characteristics of stratum and RMR. The load range due to the load height is calculated assuming block shaped and arch shape. The support load of the roof bolt was considered as the average load of the two methods. Numerical analysis results of the support design showed that the cable bolt was more effective for the roof supporting fully grouted than the anchoring type. As a result of the construction, it was possible to control the roof, but all of the roof was gradually sinking downward due to the deformation of the side wall of the mine tunnel.

• Journal of Korean Association for Spatial Structures
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• v.6 no.3 s.21
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• pp.123-130
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• 2006

This study propose cutting body portion-high strength mechanical fasteners to improve deformation capacity of High strength bolts, which are the mechanical fasteners used for End-plate connections. 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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1363-1366
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• 2005

The tiebar is used by joint for keeping from deformation by conserving tensile load between two structure. The tiebar, bolt joining type, is combined by tiebar and clevis like bolt and nut. By coupled, it maintains tensile load. While it goes through repeated load, it occurs to loose because joining force between clevis and nuts is reduced. So, continuos maintenance is needed such as making tighter periodically, repairing the broken part and so on. For that reason, this paper calculates necessary torque unfastening joint for conventional tiebar and presenting tiebar theoretically and then consider the reason that conventional bolt-typed tiebar unties. Also, through vibration untied test for two types of tiebar we confirm that presenting tiebar have a improvement of unfastening when we compare with the conventional one.

• Journal of the Korean Wood Science and Technology
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• v.28 no.4
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• pp.72-82
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• 2000

Attempts were made to analyze the behavior of single and multiple-bolted connections through theoretical methods such as European yield theory, empirical approaching method, and semi-rigid theory instead of many experimental methods that have been actually inefficient and non-economical. In the case of a single-bolted connection, if accurate characteristic values of a material could be guaranteed, it would be more convenient and economical to perform the behavior analysis using a model based on the semi-rigid theory, instead of the existing complex yield model, or the empirical formula which produces errors, giving different results from the actual ones. If the variables of equation determining the load and deformation could be appropriately controlled, the analytical method in conjunction with a semi-rigid theory could be effectively applied to obtain the desirably predicted value, considering that the appropriate solution could be derived through a simpler equation using a less difficult method compared to the existing yield model. It is concluded that analytical method with semi-rigid theory can be used in the behavior analysis of bolted connection because our developed method showed excellent analysis ability of behavior until number of bolt is two. Although our analytical method has the disadvantage that the number of bolt is limited to two, it is concluded that it has the advantage than numerical method which complicated and time-consuming.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.10a
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• pp.128-131
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• 2009

In this paper, three-dimensional finite element analysis of screw rolling process of a long shaft bolt is conducted by using a rigid-plastic finite element method based metal forming simulator AFDEX 3D. A whole sequence of cold forming processes of a long shaft bolt composed of forging and screw rolling processes is simulated to reveal the mechanism of screw formation. A mesh density control function is applied near the major plastic deformation region to achieve computational efficiency.