• Wind and Structures
• /
• v.25 no.6
• /
• pp.589-608
• /
• 2017

A novel probabilistic approach is presented for estimating the equivalent static wind loads that produce a static response of the structure, which is "equivalent" in a probabilistic sense, to the extreme dynamic responses due to the unsteady pressure random field induced by the wind. This approach has especially been developed for complex structures (such as stadium roofs) for which the unsteady pressure field is measured in a boundary layer wind tunnel with a turbulent incident flow. The proposed method deals with the non-Gaussian nature of the unsteady pressure random field and presents a model that yields a good representation of both the quasi-static part and the dynamical part of the structural responses. The proposed approach is experimentally validated with a relatively simple application and is then applied to a stadium roof structure for which experimental measurements of unsteady pressures have been performed in boundary layer wind tunnel.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2011.10a
• /
• pp.643-648
• /
• 2011

This paper deals with the ESM(equivalent source method) with the continuation of acoustic near-field for NAH(near-field acoustic holography) to overcome the finite measurement aperture effect and reconstruct the normal velocity on an arbitrarily shaped structure surface. The continuation method is an extension of the measured sound field into a region outside and is based on the Green's function relating acoustic quantities on the two conformal surfaces. This algorithm is not limited to planar surfaces and can be applied to arbitrarily shaped surfaces. The ESM is an alternative approach of BEM-based NAH for the reconstruction on a general structure. In ESM the acoustic field is represented by a set of point sources located over a surface that is close to the structure surface. The simulation results of this study shows that the reconstruction error of particle velocity on the source surface is 11% and 16% for planar and cylindrical sources separately.

• Proceedings of the KSME Conference
• /
• 2008.11a
• /
• pp.1156-1161
• /
• 2008

Nonlinear dynamic analysis is generally used in automobile crash analysis and structural optimization considering crashworthiness uses the results of nonlinear dynamic analysis. Automobile crash optimization has high nonlinearity and difficulty in calculating sensitivity. Recently the equivalent static load (ESL) method has been proposed in order to overcome these difficulties. The ESL is the static load set generating the same displacement field as the nonlinear dynamic displacement field at each time step in dynamic analysis. From various researches regarding the ESL method, it has been proved that the ESL method is fairly useful. The ESL method can mathematically optimize a crash optimization problem through nonlinear analysis and well developed static optimization. The ESL is applied to nonlinear dynamic structural optimization of the automobile frontal impact problem. An automobile bumper is optimized. The mass of the structure is minimized while some constraints are satisfied.

• Journal of Yeungnam Medical Science
• /
• v.4 no.2
• /
• pp.83-88
• /
• 1987

An analytic expression for equivalent square fields and a table are derived using the empirical representations obtained from the measured field size dependence of output for square field in a phantom. The expression is applicable to radiation fields that consistent with the following two assumptions Imposed on these representations. 1) It is a linear function of the logarithm of the field area, and 2) It is approximately the same function for both square and circular field of similar areas. In this paper, the derived tables and BJR table were consulted.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.54 no.1
• /
• pp.31-37
• /
• 2005

With biological effects by ELF(Extremely Low Frequency) magnetic field generated from power system, the transient magnetic field from electric appliances is a major issue presently. In this paper, we measured magnetic field distributions around electric appliances in view of harmonics and analyzed them by the use of an equivalent magnetic dipole moment method. This method was applied to 19 types of appliances, and their equivalent magnetic dipole moments and harmonic components were determined. The results show that this method is applicable to many appliances and the higher frequency magnetic field may induce higher current inside living bodies.

• Proceedings of the KIEE Conference
• /
• 2005.04a
• /
• pp.120-122
• /
• 2005

Magnetic field analysis of claw-pole type generator using equivalent circuit is presented in this paper. On the basis of 3D geometry and flux paths, equivalent magnetic circuit is designed and field analysis is performed by solving the circuit. Non-linear characteristic of material is considered for precise analysis results. 3D FEA is performed to verify analysis results, and flux densities in rotor and stator regions are compared. Calculated no-load back emf for field input voltage and speed are verified by experiment. Comparing to 3D FEA, presented method provides precise results with instant calculation time.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.52 no.12
• /
• pp.684-690
• /
• 2003

This paper estimates line constants of equivalent five-conductors model using the reduced equivalent method. Actually, the catenary system is considered by the equivalent five-conductors model in the electrical aspect. Therefore, we should compose the catenary system of the equivalent five-conductors model, then the line constants of this equivalent five-conductors model are calculated. This paper shows the reducing process about the real system of the field by using the proposed theory. Also the line constants of reduced system are provided in this paper.

• Proceedings of the KIEE Conference
• /
• 1988.11a
• /
• pp.17-20
• /
• 1988

The most important thing in design procedure of SCG is the exact estimation of the electromagnetic force acting on the field and amature winding. Until now, equivalent circuit method was used for the analysis or electric and magnetic performance. This paper sheds the leo dimensional analysis of electric and magnetic characteristics of SCG by Finite Element Method(FEM). Analysis by FEM provides more areolate results than that of equivalent circuit method because harmonics field generated by field current can he considered. Circuit and field equations are combined together in a equation and solved simultaneously.

• The Transactions of the Korean Institute of Electrical Engineers P
• /
• v.60 no.4
• /
• pp.220-226
• /
• 2011

This paper proposes a straightforward method of analyzing the operation characteristics for the capacitor run single-phase induction motor from the traditional equivalent circuit based on the revolving field theory. The proposed method consists of five procedures as follows: mechanical loss segregation, iron loss segregation and calculation of the equivalent circuit parameters, recalculation of parameters of the main winding side, calculation of the auxiliary winding magnetizing reactance and effective turn ratio, and analyzing the operation characteristics for this motor. When the characteristics are analyzed, the segregated mechanical and iron losses are considered as a loss resistance across input terminals of the equivalent circuit for the analysis. The validity of the proposed method is verified from the comparison between the computed results and the experimental ones for the operation characteristics.

• International Journal of Railway
• /
• v.3 no.1
• /
• pp.14-18
• /
• 2010

This paper describes design and characteristic analysis of long primary type linear synchronous motor (LSM) for high speed train system. LSM is designed using loading distribution method and magnetic equivalent circuit. For characteristic analysis of LSM, analytical and numerical methods are applied. Analytical method for solving the magnetic field distribution of the analytic model is based on the Maxwell’s equations. Using the characteristic equation and magnetic equivalent circuit, we analyze the effect of variation of parameters, and then we validate the result by comparing with numerical method by finite element method (FEM). We compare the analytical method with numerical method for analyzing the effect by variable parameters. This result will be useful of design and forecast of performance without FEM.