• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1610-1613
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• 2016

An analytical method for harmonic estimation of magnetization currents has been developed. The method is based on the results of the waveforms qualitative analysis. The calculation and the experimental results are compared. A good matching is observed.

• International Journal of Aeronautical and Space Sciences
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• v.10 no.2
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• pp.23-33
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• 2009

The inherent aeromechanical complexity of a rotor system necessitated the comprehensive analysis code for helicopter rotor system. In the present study, an aerodynamic analysis module has been developed as a part of rotorcraft comprehensive program. Aerodynamic analysis module is largely classified into airload calculation routine and inflow analysis routine. For airload calculation, quasi-steady analysis model is employed based on the blade element method with the correction of unsteady aerodynamic effects. In order to take unsteady effects - body motion effects and dynamic stall - into account, aerodynamic coefficients are corrected by considering Leishman-Beddoes's unsteady model. Various inflow models and vortex wake models are implemented in the aerodynamic module to consider wake induced inflow. Specifically, linear inflow, dynamic inflow, prescribed wake and free wake model are integrated into the present module. The aerodynamic characteristics of each method are compared and validated against available experimental data such as Elliot's induced inflow distribution and sectional normal force coefficients of AH-1G. In order to validate unsteady aerodynamic model, 2-D unsteady model for NACA0012 airfoil is validated against aerodynamic coefficients of McAlister's experimental data.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.55-57
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• 2009

This paper deals with an improved core loss calculation under the load conditions, namely, no-load, AC-load and DC-load of multi-pole PM generator from curve fitting method using modified Steinmetz equation considered anomalous loss. For an accurate calculation, magnetic field analyses in stator core considering the time harmonics are performed. And using the nonlinear finite element analysis (FEA), we applied separated rotating and alternating magnetic field to core loss calculation. In order to verify the core loss results by proposed method, the experimental system for no-load core loss measurement has been implemented with DC motor, power analyzer and manufactured PM generator. And, the analysis results with rotational speed agree extremely well with those obtained by measurement.

• Journal of KSNVE
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• v.5 no.4
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• pp.503-514
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• 1995

In the case of performing experimental modal analysis(EMA) and finite- element analysis(EFA) for a whole structure of automotive body that is composed of many complex parts, a trouble may arise from the calculation time, the capacity of memory in computers and the experimental conditions, etc. In this paper, for the vibrational analysis of automotive body model, the efficient modal synthesis method by means of dividing the whole structure into two parts and performing EMA and FEA for each part is studied. In addition, the method based on Lagrange interpolation is proposed for approximating rotational degrees-of-freedom information and linking FEA with EMA. In result, by measuring translational degrees-of-freedom information of only few points and adopting only few modes, the linking method based on Lagrange interpolation turned out to be efficient and accurate in the low frequency range.

• Journal of Welding and Joining
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• v.6 no.4
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• pp.35-43
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• 1988

Welding residual stresses were calculated by two dimensional thermal elasto-plastic analysis using element method. Complicated plastic behavior during heat transfer was simulated with time. Fist, temperature distributions. To consider time varying behavior of material properties and loading and unloading processes, iterative calculation based on initial stiffness method was carried out. The method proposed by Yamata was used in time increment control which determined the accuracy of claculation. comparison with other caculated and experimental results shows fairly good agreement.

• International Journal of Aeronautical and Space Sciences
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• v.1 no.2
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• pp.22-29
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• 2000

A method to simulate the gas turbine transient behavior is developed. The basic principles of the method and main input data required are described. Calculation results are presented in terms of whole operating regime of the engine. The influence of initial parameters such as starting engine power, moment of inertia of the rotor, fuel schedule on performance characteristics of gas turbine during transient operation is shown. In addition, the effect of bleeding air on transient behavior is also considered. For validation of the developed computer code, a comparative analysis with experimental data obtained from a heavy duty gas turbine is made. Calculation results agree well with the experimental data for the range of operating regime studied and proved applicability of the developed technique to initial design stage of control system.

• Steel and Composite Structures
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• v.22 no.2
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• pp.217-234
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• 2016

In order to investigate mechanical properties and load-bearing capacity of T-shaped Concrete-Filled Square Steel Tubular (TCFST) composite columns under eccentric axial load, three T-shaped composite columns were tested under eccentric compression. Experimental results show that failure mode of the columns under eccentric compression was bending buckling of the whole specimen, and mono column performs flexural buckling. Specimens behaved good ductility and load-bearing capacity. Nonlinear finite element analysis was also employed in this investigation. The failure mode, the load-displacement curve and the ultimate bearing capacity of the finite element analysis are in good agreement with the experimental ones. Based on eccentric compression test and parametric finite element analysis, the calculation formula for the equivalent slenderness ratio was proposed and the bearing capacity of TCFST composite columns under eccentric compression was calculated. Results of theoretical calculation, parametric finite element analysis and eccentric compression experiment accord well with each other, which indicates that the theoretical calculation method of the bearing capacity is advisable.

• Applied Science and Convergence Technology
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• v.25 no.4
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• pp.67-72
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• 2016

This article describes an electrical network analysis (ENA) method to calculate the pressure distribution of a vacuum system in a molecular flow regime. The vacuum system was modeled using electrical components. For an accurate analysis, a complexly combined pipe model, excluding entrance conductance, was employed and the pressure distribution was simulated using ENA. A vacuum system comprising three vacuum pumps was used for simplicity. In addition, the ENA results were compared with results from finite element analysis (FEA) and experimental measurements. The pressure distribution profiles estimated from ENA, performed using the LTSpice IV software, were in agreement with FEA and experimental results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.9
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• pp.1269-1274
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• 2012

In this paper, the iron loss was calculated using estimated iron loss coefficient at 650W Interior Permanent Magnet Synchronous Motor(IPMSM) and 250W IPMSM. The iron loss coefficients was estimated different according to electrical steel material used to stator and rotor core in motor. Aspect of The rotating flux field and alternating flux field was confirmed by magnetic field behavior and harmonic analysis in stator core, the iron loss was calculated using flux density by Finite Element Method(FEM) and estimated coefficients by iron loss coefficient estimation proposed in this paper. The iron loss experiment was performed for verified to iron loss calculation, and the iron loss coefficients were verified by comparison of iron loss calculation value and experimental value.

• Journal of Ocean Engineering and Technology
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• v.25 no.4
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• pp.48-53
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• 2011

Current trends in propeller design have led to the need for extremely complex blade shapes, which place great demands on the accuracy of design and analysis methods. This paper presents a new proposal for improving the prediction of propeller performance with a vortex lattice method using the lifting surface theory. The paper presents a review of the theory and a description of the numerical methods employed. For 8 different propellers, the open water characteristics are calculated and compared with experimental data. The results are in good agreement in the region of a high advanced velocity, but there are differences in the other case. We have corrected the parameters for the trailing wake modeling in this paper, and repeated the calculation. The new calculation results are more in agreement with the experimental data.