• Transactions of Materials Processing
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• v.7 no.4
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• pp.347-353
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• 1998

A new approach of elastic finite element to die stress analysis in forging is presented in this paper. The die set analysis problem is formulated by considering contact problems under both mechanical and thermal loads. In the approach, amount of shrink fit is controlled by thermal load i.e., temperature difference between die insert and shrink fits. The loading conditions are extracted automatically from a forging simulator. The predicted solution is compared with analytical one and it has been shown that the predicted results are in excellent agreement with the analytical ones. An application example is given, which was found in a cold forging company.

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.20-24
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• 2004

In this paper, a pattern/position tolerance analysis is visited on the insert to mount spacecraft electronic equipment. SQP(Sequential Quadratic Programming) is used to obtain the position tolerance. For examples, the cases of RDU(Remote Drive Unit) and OBC(On Board Computer) in the KOMPSAT-2 STM(Structure and Thermal Model) are analyzed.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.419-424
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• 2001

The purpose of this study is comparing cold expansion method with interference fit. Cold expansion method and interference fit of fastener hole is using in the aerospace industry. These treatment lead to an improvement of fatigue life to the compressive residual stresses developed on the hole surface. But Research is nothing to about difference effect of between cold expansion method and interference fit. So In this paper, It is shown that Comparing cold expansion method with interference fit. and It is further shown that residual stress distribution according to plate thickness.

• Journal of the Korean Society for Advanced Composite Structures
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• v.4 no.3
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• pp.1-6
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• 2013

In this study, a shape of connector on seismic reinforced strip, which did not cause any physical damage to concrete column and can repair and reinforcement was decided by using nonlinear finite element analysis. Load displacement was applied on the concrete attached by strip. Stress distribution of connector by extension of concrete were checked. Through stress distribution of this analysis results, the most favorable shape was selected as a shape of the connector.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.470-474
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• 2000

Cold expansion of fastener holes is a mechanical process widely used in the aerospace industry. This treatment leads to an improvement of fatigue behavior due to the developed compressive residual stresses on the hole surface. The residual stress profile depends on the parameters of cold expansion, which are, expanding rate, inserting direction of mandrel, material properties etc. and the method to confirm this profile is only measurement by X-ray diffractometer. Despite its importance to aerospace industries, little attention has been devoted to the accurate modelling of the process. In this paper, Two-dimensional axisymmetric finite element simulations have been conducted for the cold expansion in an aluminium plate in order to predict the magnitude and distribution of the residual stress and plastic deformation. Maximum compressive residual stress could be increase about 7 percent using the 2-step cold expansion method.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.5
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• pp.400-407
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• 2011

The stress distribution and stress amplitude of a membrane are major factors to decide the mechanical fatigue life of PEMFC (Polymer Electrolyte Membrane Fuel Cell). In this paper, mechanical stresses under operating hygro-thermal condition of the membrane are numerically modelled. Contact analysis between gas diffusion layer (GDL) and the membrane is performed under various temperature-humidity conditions. The structural model has nonlinear material properties depending on temperature and relative humidity. Several geometric conditions are applied to the model. The numerical analysis results indicate that deformations of the membrane are strongly related with assembly conditions of the fuel cell. The fatigue life is predicted for practical operating condition through experimental data.

• The Korean Society of Law and Medicine
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• v.19 no.1
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• pp.207-254
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• 2018

The major court rulings delivered in 2017 include the ruling that separated the legal character of denture production agreement signed together with medical care agreement and found a subcontracting dimension in the former, and the ruling that overcame the limitations of the theory of entire appearance of a fetus as discussed in civil law by using the legal principle of insurance which suggests that unborn child insurance takes effect after the contract is signed and the first installment of the premium is paid in. As more court rulings find the medical specialists responsible for accidents and injuries from drugs, some argue that medication counseling by the druggist who makes and dispenses drugs should be upgraded. And with respect to a court ruling that denied the hospital's responsibility for an infection-involving accident even if there were no records on specific measures taken in infection management, some criticized the court for being too conservative in recognizing responsibilities. And with respect to infectious disease management, some criticized the court for its interpretation and application of the facts in the direction of denying the negligence. In addition, some claimed that it is necessary to establish institutional system for hospital infection control and its aid for victims, and to improve the system including the reversal of the burden of proof given the special nature of hospital infections. A number of rulings on the duty to disclose included the one which stated that the specific matter did not require a doctor's explanation as it was explained or the specific medical service would have been performed even if no explanation had been given. There was a greatly controversial ruling over the scope of indemnification, which accepted the occurrence of multiple scars and deformation as disorders while regarding breast as a thoracic organ. And a Supreme Court ruling over interpreting Medical Service Act was criticized as overstepping the boundary allowed in the law.

• Journal of Korean Society of Steel Construction
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• v.27 no.2
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• pp.251-260
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• 2015

The end plate connection is applied to beam-column moment connections in various forms. Such end plate connection displays changes in the behavioral characteristics, strength and stiffness, and energy dissipation capacity based on the thickness and length of the end plate, the number and diameter of the high strength bolt, the gauge distance of the high strength bolt, prying action force of the high strength bolt, and dimensions and length of the welds. Accordingly, this study has apprehended the axial tensile stiffness and prying action force of the high strength bolt connected on the tensile side based on the difference in thickness of the end plate, and was conducted to propose an analysis model for the prediction of such variables that affect the operating properties of the end plate. To achieve this, this study has conducted a three-dimensional non-linear finite-element analysis of the unstiffened expanding end plate connection by selecting only the thickness of the end plate as the variable.

• Journal of the Korean Geotechnical Society
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• v.31 no.9
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• pp.29-38
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• 2015

In this study, track dynamic interaction characteristics caused by the vehicle running through transitional section such as bridge abutments were studied using the finite element analysis program. The geometric condition of track was generated by trigonometric function and allowable maximum track irregularity is determined by KORAIL track maintenance criteria. The sub-infrastructure under rail fastener system was modelled by 3D solid elements. To reduce computational cost only half track line is numerically considered and the roller boundary condition was applied to each side of model. In this study, the vehicle-track dynamic interaction analysis was carried out for standard Korean transition section of concrete track and the dynamic behaviors were investigated. The dynamic characteristics considered are wheel load variation, vertical acceleration at body, and maximum Mises stress at each part of transitional section.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2464-2472
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• 2011

Train runs on high speed and the concrete track is constructed. Rail fastening device needs to reduce elasticity, transferred load, noise, and vibration etc. Consequently, low elastic pad has a great impact of the durability and stability of the track. In this study, discussed in previous studies, static numerical analysis and real scale repeated loading test, followed by dynamic response analysis were implemented. The most distinctive characteristics of the model proposed is to simulate the real wheel behavior on rail. And the main analysis object is to evaluate and compare the deformation characteristics of the transition track while load reduction effect of transfer on roadbed assessed by various low elastic pad.