• Transactions of the Korean Society of Mechanical Engineers B
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• v.24 no.1
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• pp.39-49
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• 2000

This paper presents the modeling approach that can predict transient behavior of rotary compressor. Mass and energy conservation laws are applied to the control volume, real gas state equation is used to obtain thermodynamic properties of refrigerant. The valve equation is solved to analyze discharge process also. Dynamic analysis of vane and roller is carried out to gain friction work. From the above modeling, the performance of rotary compressor with radial clearance and friction loss is investigated numerically. The performance of each refrigerant is estimated, respectively by applying R12, R134a, and R290/ R600a mixture.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.20 no.6
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• pp.1854-1861
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• 1996

A reliable and practical finite element modeling technique to estimate the behavior of complex structures with bolted joints is important for engineeres in the industry. Accordingly, we have examined several simplified modeling techinques which do not require the use of special elements such as a gap eloement. The dynamic and static erxperiments have confirmed that the technique to model the bolted joints with eight-noded three dimensional elemnts which fill the bolt space gdives most satisfactory results.

• Journal of KSNVE
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• v.10 no.2
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• pp.319-324
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• 2000

This paper shows hot to model the submerged elastic structures and adequate analysis tools for modal behavior when using finite element and boundary element method. Four different cases are reviewed depending on the location of the water and air. First case is that structures are filled with air and water is located outside. Second case is opposite to case one. These cases are solved by direct approach using collocation procedure. Third case is that water is located both sides of structures. Last case is that air is located both sides. These cases are solved by indirect approach using variational procedure. As analysis tools harmonic frequency sweep analysis and eigenvalue iteration method are selected to obtain the natural frequencies of vibrating submerged structures depending on the cases. Results are compared with closed form solutions of submerged spherical shell.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.175-180
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• 1998

The U-Zr metallic alloy with low swelling HT9 cladding is the candidate for the KALIMER fuel rod. The fuel rod should be able to maintain the structural integrity during its lifetime in the reactor. In a typical metallic fuel rod, load is mainly applied by internal gas pressure, and the deformation is primarily caused by creep of the cladding. The three-dimensional FEM modelling of a fuel rod is important to predict the structural behavior in concept design stage. Using the ANSYS code, the 3-D structure analyses were performed for various configuration, element and loads. It has been shown that the present analysis model properly evaluate the structural integrity of fuel rod. The present analysis results show that the fuel rod is expected to maintain its structural integrity during normal operation.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.157-159
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• 2008

This paper describes modeling and analysis of magnetic inrush for a 765kV transformer using EMTP-RV. EMTP-RV generates the core flux and thus helps show the behavior of the core, i.e. hysteresis characteristics. The results of three kinds of the magnetic inrush such as initial inrush, sympathetic inrush, and recovery inrush are included. This modelling can help the design of a protection relay for a transformer.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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• pp.47-53
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• 2005

The non-linear finite element program of the large deformation analysis by computer simulation has been used in the prediction and evaluation of the behaviors of the non-linear rubber components. The analysis of rubber components requires the tools modelling the special materials that are quite different from those used for the metallic parts. The nonlinear simulation analysis used in this study is expected to be widely applied in the design analysis and the development of several rubber components which are used In the manufacturing process of many industries. By utilizing this method, the time and cost can also be saved in developing the new rubber product. The objective of this study is to analyze the rubber component with the large deformation and non-linear properties.

• Tribology and Lubricants
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• v.18 no.6
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• pp.402-410
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• 2002

In this study, a hydrodynamic analysis of the reciprocating compressor crankshaft considering a finite bearing modelling of the journal bearings used in small refrigeration compressors is performed. In the problem formulation of the compression mechanism dynamics, all corresponding hydrodynamic forces and moments are considered using the finite bearing analysis in order to determine the crankshaft trajectory at each step. The solution of the Reynolds' equation is determined numerically using a finite difference method and a Newton-Raphson procedure was employed in solving the dynamic equations of the crankshaft. The crankshaft orbits fur the finite bearing model and short bearing theory were used to compare the effect of the hydrodynamic farces of the journal bearings on the dynamic and lubrication characteristics of the crankshaft-journal bearing system. Results show that the finite bearing model for the journal bearings must be considered in calculating for the accurate dynamic characteristics of the reciprocating compressor crankshaft.

• Steel and Composite Structures
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• v.19 no.4
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• pp.789-809
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• 2015

This paper presents experimental and numerical studies into the structural behavior of a high performance corbel type composite connection adopted in Raffles City of Hangzhou, China. Physical tests under both monotonic and quasi-static cyclic loads were conducted to investigate the load carrying capacities and deformation characteristics of this new type of composite connection. A variety of structural responses are examined in detail, including load-deformation characteristics, the development of sectional direct and shear strains, and the history of cumulative plastic deformation and energy. A three-dimensional finite element model built up with solid elements was also proposed for the verification against test results. The studies demonstrate the high rigidity, strength and rotation capacities of the corbel type composite connections, and give detailed structural understanding for engineering design and practice. Structural engineers are encouraged to adopt the proposed corbel type composite connections in mega high-rise buildings to achieve an economical and buildable and architectural friendly engineering solution.

• Structural Engineering and Mechanics
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• v.39 no.3
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• pp.317-338
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• 2011

Three-dimensional thermal and mechanical coupled finite element models are proposed to study the structural behaviours of shear connectors under fire. Concrete slabs, steel beams and shear connectors are modelled with eight-noded solid elements, and profiled steel deckings are modelled with eight-noded shell elements. Thermal, mechanical and geometrical nonlinearities are incorporated into the models. With the proper incorporation of thermal and mechanical contacts among steel beams, shear connectors, steel deckings and concrete slabs, both of the models are verified to be accurate after the validation against a series of push-out tests in the room temperature or under the standard fire. Various thermal and mechanical responses are also extracted and observed in details from the results of the numerical analyses, which gives a better understanding of the structural behavior of shear connectors under elevated temperatures.

• Computers and Concrete
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• v.5 no.4
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• pp.417-434
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• 2008

This paper deals with damage induced anisotropy modeling for concrete-like materials. A thermodynamics based constitutive relationship is presented coupling anisotropic damage and elasticity, the main idea of the model being that damage anisotropy is responsible for the dissymmetry tension/compression. A strain written damage criterion is considered (Mazars criterion extended to anisotropy in the initial model). The biaxial behavior of a family of anisotropic damage model is analyzed through the effects of yield surface modifications by the introduction of new equivalent strains.