• Journal of Ocean Engineering and Technology
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• v.18 no.5
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• pp.36-42
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• 2004

Orthotropic laminates, such as [$0^{\circ}6$/$90^{\circ}6$]s and [$90^{\circ}6$/$0^{\circ}6$]s, were performed, using a commercial nonlinear finite element method. Interlaminar stress distributions, around the hole curve free-edge, were calculated. The delamination bearing strengths of pin joints were predicted, using the modified delamination failure criterion. These stress distributions were presented along the radial lines and around the free-edge of the hole. Further, three-dimensional non-linear contact analysis of orthotropic laminates was conducted to investigate the effect of friction. In this paper, laminates with a circular hole were taken to study interlaminar stresses the curved edge. This study may assist in the design of a thick composite laminate with mechanically pin joints.

• Journal of Mechanical Science and Technology
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• v.16 no.4
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• pp.492-500
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• 2002

This paper presents a study of the effect of varying the roll gap of oval pass in round-oval-round pass sequence on the interracial slip of workpiece, entrance and exit velocities, stresses and roll load that the workpiece experiences during rolling, by applying analytical method, finite element simulation and verification through hot bar rolling tests. The results have shown that the roll gap variation of oval pass affects the interfacial slip of workpiece along the groove contact and the specific roll pressure. The optimum conditions in terms of minimum interfacial slip and minimum specific roll pressure, which might influence the maximum groove life, is obtained when the subsequent round pass is completely filled.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.212-217
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• 2000

The reliable determination of the stress intensity factors for cracks in bolted Joints is needed to evaluate the safety and fatigue life of them widely used in mechanical components. The weight function method is an efficient technique to calculate the stress intensity factors for various loading conditions using the stresses of an uncracked model. In this paper the mixed-mode stress intensity factors for cracks in bolted joints are obtained by weight function method, in which the coefficients of weight function are determined by finite element analyses far reference loadings. The effects of the magnitude of clearance and factional coefficient on the stress intensity factors are investigated.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.2
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• pp.162-167
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• 2003

This paper is the study on stress analysis for tooth modification of high speed gear using a finite element method. Gear drives constitute very important mechanisms in transmitting mechanical power processes which compromise several cost effective and engineering advantages. The load transmission which occurred by the contacting surfaces arises variable elastic deformations evaluated through finite element analysis. The automatic gear design program was developed to model gear shape precisely. This developed gear design system was used by pre-processor of FEM packages. The distribution of stresses at contacting surfaces was examined when gear tooth contacts. And this paper proposes a method for the tooth modification after carrying out stress analysis using a finite element method.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.413-414
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• 2006

This study was aimed to verify the stable interruption characteristics between power collector and 3rd rail type conductor rail for the Korean-standardized rubber-tired AGT light rail vehicle. At the test track for the Korean-standardized rubber-tired AGT light rail vehicle, interruption ratios, stresses, vibrations, and contact force variations were measured by test conditions, having various train speed. As the results, it was verified that developed 3rd rail type conductor maintains interruption characteristics, which can supply stable electric power.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1997.04a
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• pp.42-48
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• 1997

The dynamic response of symmetric cross-ply and angle-ply composite laminated plates under impact loads is investigated using a higher order shear deformation theory. A modified Hertz law is used to predict the impact loads and a four node finite element is used to model the plate. By using a higher order shear deformation theory, the out-of-plane shear stresses, which can be a crucial factor in the failure of composite plates, are determined with significant accuracy. The results compared with previous investigations showed good agreement. The effect of ply sequence and ply angle on the contact force is also studied.

• Journal of the korean Society of Automotive Engineers
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• v.13 no.6
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• pp.101-108
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• 1991

During torsional fatigue of externally cracked cylindrical specimen, crack face rubbing may occur. At this time, normal contact forces arise when shear displacements cause the crack faces to be wedged open due to mismatch of the fracture surface asperities. These normal forces, in turn, generate friction force which act in opposition to the applied shear stresses and reduce the effective stress intensity factor. The premise of the proposed work is that friction and wedging can be studied by measuring the shear and normal displacement across the crack mouth. We have measured the crack mouth compliance using the new biaxial extensometer.

• Journal of the Korean Society for Railway
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• v.6 no.1
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• pp.21-28
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• 2003

Environment-dependent fatigue life of Cu-Cd alloy wires used as messenger wires was investigated. Tensile test results showed the decrease of tensile strength and elongation of messenger wires by 3.7% and 16.8%, respectively, in used specimens when compared to new ones. Messenger wires used at industrial region for 26 yeras showed 35∼50% decrease in fatigue life, which is partly due to the in stress concentrations by formation of corrosion products at the surface. Single wires showed better fatigue properties than stranded wires, especially at low cycle regions with higher stresses. Stranded wires showed shorter fatigue lives than single wires because of friction between wires by surface contact. Service life of messenger wires was dependent upon the environments which they were exposed to. SO$_2$ and humidity deteriorated the fatigue properties by environmental degradation.

• Journal of Ocean Engineering and Technology
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• v.14 no.4
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• pp.62-97
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• 2000

Recently the research for utilization of waste heat produced from electric power plants, casting factories, heat treating factories or commercial are being afforded by the need for energy saving. The objective of this study is to develop a thermoelectric generation system which unused energy from close-at-hand sources such as garbage incineration heat and industrial exhaust etc. into electricity. This paper a thermoelectric technology on a optimum system design method and efficiency and cost effective thermoelectric element on order to extract the maximum power output from energy conversion of waste energy. It is shown that the longitudinal stresses of module contacted with two point constrained Al tubes could be released more than those with a one-point constrained.

• Geomechanics and Engineering
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• v.1 no.1
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• pp.97-112
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• 2009

The interactions between a granular pile and raft placed on top are investigated using the continuum approach. The compatibility of vertical and radial displacements along the pile - soil interface and of the vertical displacements along the raft - top of ground interfaces are satisfied. Results show that consideration of radial displacement compatibility does not influence the settlement response of or sharing of the applied load between the granular pile and the raft. The percentage load carried by the granular pile (GP) increases with the increase of its stiffness and decreases with the increase of the relative size of raft. The normal stresses at the raft - soil interface decrease with the increase of stiffness of GP and/or relative length of GP. The influences of GP stiffness and relative length of GP are found to be more for relatively large size of raft. The percentage of load transferred to the base of GP increases with the increase of relative size of raft.