• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.15-20
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• 2003

Most engineering products contain more than one component. Failure occurs either at the connection itself or in the component at the point of attachment of the connection in many engineering structures. The allocation and design of connections such as bolts, spot-welds, adhesive etc. usually play an important role in the structure of multi-components. Topology optimization of connection component provides more practical solution in design of multi-component connection system. In this study, a topology optimization based on density distribution approach has been applied to optimal location of fasteners such as T-shape, L-shape and multi-component connection system. From the results, it was verified that the number of iteration was reduced, and the optimal topology was obtained very similarly comparing with ESO method. Therefore, it can be concluded that the density distribution method is very suitable for topology optimization of multi-component structures.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.311-316
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• 2007

The improvement of speed and ride comfort requires a very horizontally and vertically rigid and non-flexible alignment. It is inevitable to construct many bridges depending on the topography of landscapes and obliged to lay turnouts on the bridges. In that case, special considerations have to be taken into account, i.e. permissible stresses of turnout components and limitations of displacements of bridge and turnouts. In this studies, numerical analyses for turnout/bridge interaction are carried out using commercial program LUSAS. The target of analytical model is the turnout layed near Pyeongrae-Hopyeng station on Kyeongchun line. The lead rail, stock rails, and the bridge are modelled using beam elements. Fasteners and ballast resistances are modelled using bi-linear spring elements. The turnout behaviors are investigated by varying the parameters such as span length of bridge, spring coefficients, and thermal loads.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.05a
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• pp.653-657
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• 2000

Machining performance in hard turning of hardened AISI M2 steel has been studied. Ceramic tools were used in the cutting tests without coolants and workpiece was prepared by heat treatment to increase its hardness up to Rc 60. Cutting state parameters such as cutting forces, temperature, and tool wear were measured in the experiments and effects of tool wear on cutting states were investigated.

• Steel and Composite Structures
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• v.22 no.1
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• pp.79-89
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• 2016

Cold formed steel shear panel is one of the main components to bearing lateral load in low and mid-rise cold formed steel structures. This paper uses finite element analysis to evaluate the stiffness, strength and failure mode at cold formed steel shear panels whit steel sheathing and nonlinear connections that are under monotonic loading. Two finite element models based on two experimental model whit different failure modes is constructed and verified. It includes analytical studies that investigate the effects of studs and steel sheathing thickness changes, fasteners spacing at panel edges, one or two sides steel sheathing and height-width ratio of wall on the lateral load capacity. Dominant failure modes include buckling of steel sheet, local buckling in boundary studs and sheet unzipping in the bottom half of the wall.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.15 no.6
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• pp.44-49
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• 2006

The use of snap-fit features is highly recommended to reduce overall product cost and manufacturing time by reducing the number of parts and eliminating assembly with conventional fasteners. Application to particular product for integral attachment using snap-fit features is needed. Alternative attachment concept for specific application has been introduced. In this study, the optimal attachment design based on the given design objectives is identified using newly developed alternative attachment concept for the specific application to LCD monitor case assembly. Integral attachment using snap-fit features applies the systematic procedure and the intensity analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.3 s.258
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• pp.338-343
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• 2007

Thermal deformation of cast iron exhaust manifold for turbo diesel engine is investigated by finite element analysis (FEA). The FE model included the temperature dependent material properties as well as the interactions between exhaust manifold, cylinder head and fasteners. It also considers the sliding behavior of the flanges of exhaust manifold on cylinder head when either expansion or contraction of the exhaust manifold exceeds the fastener pretension. The result of analysis revealed that remarkable thermal deformation along the longitudinal direction. Compressive plastic deformation at high temperature remained tensile stress in manifold and resulted in longitudinal contraction at ambient temperature. The amount of contraction at each fastener position was predicted and compared with experimental results. Analysis results revealed that the model predicted deformation qualitatively, but more elaborated cyclic hardening behavior would be necessary to predict the deformation quantitatively.

• Journal of the Korean Society for Precision Engineering
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• v.32 no.1
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• pp.83-88
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• 2015

At the early stages of engineering design, a number of design concepts may be suggested. With a great degree of freedom, making a good choice may be a challenge at this stage. In this study, a simplified evaluation criterion for design concepts is presented based on cost, simplicity and safety. Cost is estimated by the amount of materials and the required level of tolerance. Simplicity is represented by the number of parts, assembly steps, and fasteners. Safety is assessed by the level of potential failure. The proposed criterion is applied to an example design of driving mechanisms for cervical vertebrae massage machine.

• Proceedings of the Safety Management and Science Conference
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• 2008.04a
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• pp.417-428
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• 2008

Designers have to consider voice of customer, process capability, manufacturing standards & condition, manufacturing method, characteristics of products to decide tolerances. Especially, in case of position of hole and pin, designers have to consider process capability to decide tolerances. The traditional position tolerances used in a drawing are theoretical values which are allocated to position under the worst case assembling condition that both hole and pin are the maximum material condition(MMC). However, When the process capability is high, more exact product size can be produced under stable manufacturing condition. larger clearance of hole and pin can be allocated. In this point of view, manufacturer could increase the yield by allocating larger position tolerance than theoretical position tolerance of hole and pin considering process capability.

• Journal of the Korea Safety Management & Science
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• v.11 no.1
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• pp.75-85
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• 2009

Designers have to consider voice of customer, process capability, manufacturing standards & condition, manufacturing method and characteristics of products to decide tolerances. Especially, in case of position of hole and pin, designers have to consider process capability to decide tolerances. The traditional position tolerances used in a drawing are theoretical values which are allocated to position under the worst case assembling condition that both hole and pin are the maximum material condition(MMC). However, when the process capability is high, more exact product size can be produced under stable manufacturing condition. Larger clearance of hole and pin can be allocated. In this point of view, manufacturer could increase the yield by allocating larger position tolerance than theoretical position tolerance of hole and pin considering process capability.

• Proceeding of KASS Symposium
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• 2006.05a
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• pp.182-188
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• 2006

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