• Journal of the Korean Society for Precision Engineering
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• v.19 no.2
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• pp.171-176
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• 2002

This paper is the study on stress analysis of spur gear using a finite element method. Gear drives constitute very important mechanisms in transmitting mechanical power processes compromising several cost effective and engineering advantages. The load transmission occurred by the contacting surfaces arises variable elastic deformations which are being evaluated through finite element analysis. The automatic gear design program is developed to model gear shape precisely. This gear design system developed was used by pre-processor of FEM packages. The distribution of stresses at contacting surfaces was examined when a pair of gear contact.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.5
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• pp.820-830
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• 1989

The tire inflation and contact problem has been solved by a finite element method. The finite element formulation is derived from the equilibrium equations by the principle of virtual work in the form of an updated Lagrangian formulation for incremental analysis. Then, a contact formulation is added to the finite element formulation to calculate stress state of tire in contact with flat rigid road under the load due to the self-weight of a vehicle. In the finite element analysis, equations of effective material properties are introduced to analyze a plane strain model of the shell-like tire by considering the bending effect of reinforced steel cords. The proposed equations of effective material properties produced stress concentration around the edge of belt layers, which does not appear when other well-known equations of material properties are adopted. The result from the above algorithm demonstrates the validity of the formulation and the proposed equations for the effective elastic constants. The result fully interprets the cause of separation between belt layers by showing the stress concentration.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.4
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• pp.403-407
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• 2010

Gecko adhesion system consists of beam-shaped seta and spatula which has the role of adhesive pad. In this paper, adhesion mechanism of gecko adhesion system is performed by using adhesive beam contact model. this model has a feature of non-uniform stress profile on the contact surface and adhesion/detachment mechanism is determined by the tensile stress of the contact region. a spatula tip pad has the role of reduction of maximum tensile stress and adhesive force is increased due to this effect. As for a reverse loading case, maximum compressive stress drops by the spatula effect and this cause unsymmetric loading conditions between adhesion and detachment forces. In this study, finite element method is used for the analysis of adhesive beam contact model and the results for spatula effect are presented.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.6
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• pp.1784-1797
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• 1996

The disk/blade assembly of a turbine engine is made in the shape of a dovetail type or a fir-tree type. Since disk fillet regions or contact surfaces undergo high stress comcentration, fatigue cracks frequentrly occur in the disk/blade assembly. Therefore, it is necessary to analyze the stress distributions in the fir-tree type disk/balde assembly and predict the region of fatigue failure. The stress distributions of the disk/blade assembly were investigated by using the photoelastic method and the finite element method. Two dimensional photoelastic techniques were used to investigate the stress distributions of contact surfaces and fillet regions. TH stress distributions were obtained by the shear-difference method and were compared to the finite element results. It was found that maximum tensile stresses were higher in the fillet region thatn in the contact surfaces of the fir-tree models. The finite element results showed good agreement with the experimental results.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.497-502
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• 2004

This paper presents applications of the objective stress rates to stress update algorithms for transient shell dynamic analysis within the context of explicit time integration. The hypo elasto-plastic materials are assumed in establishing constitutive equations. The derivation of the objective stress rates are investigated by use of the Lie derivative. Comparison results are given between the Kirchhoff and Cauchy stress formulation. The Jacobian determination algorithm proposed in this paper is presented in association with the Belytschko-Lin-Tsay shell theory. Several numerical examples are demonstrated including contact and non-contact examples, by which proposed algorithms are compared with respect to the accuracy and effectiveness.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.351-353
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• 1999

In this paper, electric field analysis of 170kV class GCB is carried out. Considering the movement of arcing contacts during circuit interruption, electric field analysis between moving and fixed contacts is performed with changing the stroke length. From analysis results, electric field stresses are high at stationary arcing contact, moving arcing contact and varies at changing nozzle shapes. Specially, the stationary arcing contact shape has an significant effect on the capacitive small current interruption and the reduction of the electric field stress at this area is important. Varying the shape of stationary arcing contact, electric field analysis is carried out and the optimal shpae of the fixed arcing contact where the electric field stress is low is designed.

• Structural Engineering and Mechanics
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• v.36 no.1
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• pp.95-110
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• 2010

Two-dimensional elastic contact problems, including normal, tangential, and rolling contacts, are treated with the finite element method in this study. Stress boundary conditions and kinematic conditions are transformed into multiple point constraints for nodal displacements in the finite element method. Upon imposing these constraints into the finite element system equations, the calculated nodal stresses and nodal displacements satisfy stress and displacement contact conditions exactly. Frictional and frictionless contacts between elastically identical as well as elastically dissimilar materials are treated in this study. The contact lengths, sizes of slip and stick regions, the normal and the shear stresses can be found.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2000.11a
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• pp.44-49
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• 2000

Recently, PM-high speed steel(PM-HSS) has reportedly been a good alternative material for rolling mill because of its superior peformance to conventional HSS. This paper has been aimed to investigate the possibility for application to rolling contact element for PM-HSS by X-ray diffraction technique. The X-ray elastic constant for PM-HSS has been found by X-ray diffraction during the four-point bending test. Residual stress and half-value breadth on the contact surface during rolling contact fatigue process by X-ray diffraction have also been measured. The result of this study shows that the application of X-ray diffraction technique to PM-HSS could be as possible alternative material as conventional HSS. Half-value breadth on rolling contact surface by X-ray diffraction is not changed during rolling contact fatigue process. On the other hand, the residual stress is changed. This suggests that dislocation reaction has been hardly occurred in rolling contact, depending on supersaturated carbon in PM-HSS.

• Journal of Korean Association for Spatial Structures
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• v.2 no.4 s.6
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• pp.53-60
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• 2002

An analytic study on the bond stress between steel tube and concrete in concrete filled steel(CFT) rectangular column is presented in this paper. Recently buildings need members which are enhanced durability and ductility. Concrete filled rectangular column system is proposed as alternative plan. In this paper, ABAQUS/Standard Version 5.8 which is identified as usefulness for finite element analysis and has various element library is used. The variables in this study are the location and type of shear-connector. The modeling on contact problem practiced by Contact Pair and Contact Pressure method. In the step of physical bond, it is practiced by Change friction option After yielding of models, analytic results is less than that of experimental results.

• The Journal of Korean Academy of Prosthodontics
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• v.34 no.3
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• pp.632-649
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• 1996

The purpose of this study was to examine, by the method of 3-dimentional finite element analysis. how infraocclusion affected the stress distribution in surrounding bone and osseointegrated prosthesis. The 3-dimentional finite element mandibular models were made, in which the first and second molars were removed and the two osseointegrated implants were placed in the first and second molar sites and implant supported fixed prostheses were constructed. Analysis of equivalent stress and displacement induced by strong occlusion or infraocclusion was performed under vertical or inclined distributed loads. The results were as follows; 1. Under vertical load of 50N or 500N, the model in which infraocclusion had not been allowed showed greater stress on implants and the supporting bone than on natural teeth. 2. In the model in which infraocclusion of $30{\mu}m$ had been allowed, implant-prosthesis on the molars had no contact with opposing teeth under vertical load of 50N, However with the same allowed infraocclusion and the model under vertical load of 500N, implant prosthesis on the second molar had contact with opposing teeth, and stress distribution occured properly on natural teeth and implants. 3. Under $45^{\circ}$ inclined load, the model in which infraocclusion had not been allowed showed greater stress on implants and the supporting bone than on natural teeth. There was greater stress in the case of $45^{\circ}$ inclined load than in the case of vertical load. 4. Under $45^{\circ}$ inclined load of 50N or 500N, the model in which infraocclusion of $30{\mu}m$, had been allowed showed no occlusal contact on the implants and occlusal contact on the natural teeth. 5. In partially edentulous cases with implant supported prosthesis, we can prevent excessive load on implants by allowing infraocclusion.