• Journal of Aerospace System Engineering
• /
• v.12 no.3
• /
• pp.1-8
• /
• 2018

The fuel pump, which is used for an aircraft, was first developed in Korea through the Civil-Military Dual Components Development Program. The BLDC motor type, which is superior to the DC brush motor when considering efficiency, endurance, and explosive environmental characteristics, was applied to the fuel pump given its capacity and operating condition. The magnetic flux of the permanent magnet was analyzed based on the magnet flux density equation, using the Maxwell equation and the environmental condition. The motor performance, according to the load, was analyzed using the finite element method in order to design validation. The motor assembly was developed by designing the motor drive and the EMI filters. The performance test results of the motor assembly for the fuel boost pump were consistent with the analysis.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.39 no.5
• /
• pp.425-433
• /
• 2015

In this paper, we have numerically investigated two-dimensional dielectrophoretic (DEP) motions of a single particle suspended freely in a viscous fluid, interacting with a nearby nonconducting planar wall, under an externally applied uniform direct-current electric field. Particularly, we solve the Maxwell equation with a large sharp jump in the electric conductivity at the particle-fluid interface and then integrate the Maxwell stress tensor to compute the DEP force on the particle. Results show that, under an electric field parallel to the wall, one particle is always repelled to move far away from the wall and the motion depends strongly on the particle-wall spacing and the particle conductivity. The motion strength vanishes when the particle is as conductive as the fluid and increases as the conductivity deviates further from that of the fluid.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.7 no.2
• /
• pp.31-37
• /
• 2008

In this paper, we analyzed the dynamic behavior of magnetic fluid in a circular pipe with multiple permanent magnets. Magnetic fluid react on magnetic field against the normal fluid. In other words, magnetic fluid flow has the electromagnetism and fluid mechanics. So magnetic fluids has studied about the fluids properties and experiment. In this paper we studied the magnetic fluids velocity and pressure distribution for the novel type actuator. Because the velocity and pressure distribution is the important element of the magnetic fluids flow. First, we analyzed the Maxwell equation for the multiple permanent magnet and then concluded the governing equations for the magnetic fluid flow using the equation of Navier-Stokes. And, we simulated the dynamic behavior of magnetic fluid flow using the FEM(Finite Element Method). And we illustrated the relation between magnetic field and dynamic behavior of magnetic fluid flow.

• Korean Chemical Engineering Research
• /
• v.60 no.4
• /
• pp.613-619
• /
• 2022

The extended Maxwell-Wagner polarization model is employed to describe the ER(Electrorheological) behavior of bi-dispersed ER suspensions, and solutions to the equation of motion are obtained by dynamic simulation. Under the same particle volume fraction, it is found that the dynamic yield stresses of uniform size suspensions do not depend on the particle size. Compared with uniform size suspensions, the dynamic yield stress is reduced for ER fluids consisting of two kinds of particles with different sizes. Compared with the dynamic yield stress behavior, for ${\dot{\gamma}}^*$≧0.01 the shear stress shows different behaviors depending on the particle sizes and the raio of different size particles. The simulation results show the nonlinear ER behavior (∆_𝛕 ∝ Eⁿ, n ≈ 1.55) of the conducting particle ER suspensions.

• Journal of the Optical Society of Korea
• /
• v.1 no.2
• /
• pp.67-73
• /
• 1997

Light wave diffraction from multiple superposed volume gratings is inestigated using a perturbative iteration method of the integral equation of Maxwell's wave equation. The host material and index gratings are anisotropic and non-coplanar multiple volume gratings are considered. In this method, the paraxial approximation and lack of backward scattering in conventional coupled mode theory are not assumed. Systematic analysis of anisotropic wave diffraction due to multiple noncoplanar volume index gratings is performed in increasing level of diffraction orders corresponding to successive iterations.

• Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
• /
• 2001.02a
• /
• pp.102-103
• /
• 2001

In this paper we calculate the AC Loss in the superconducting slab carrying ac transport current. Magnetic diffusion equation for computation of the electric field and current distribution are based on Maxwell's equations and non-linear constitutive equation. The E-J characteristics of superconductor are applied to computation. We will present the result of the high-temperature superconductor case comparison with the slab of low temperature superconductor.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.39 no.5
• /
• pp.445-452
• /
• 1990

In order to design a conveyer system which is driven by short primary single sided linear induction motors (SLIM), the thrust force characteristics of SLIM have been calculated from the fundamental equation based on Maxwell's electromagnetic equation and by varying the various design parameters. A conveyer system of moving secondary has been constructed using the design values obtained by the simulation and these values are compared with the experimental values. The control method of the conveyer system is also proposed.

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.30 no.4D
• /
• pp.387-393
• /
• 2010

This paper studies static crack growth of asphalt pavement using the extended finite element method (XFEM). To consider nonlinear characteristics of asphalt concrete, a viscoelastic constitutive equation using the Maxwell chain is used. And a linear cohesive crack model is used to regularize the crack. Instead of constructing the viscoelastic constitutive law from the Prony approximation of compliance and retardation time measured experimentally, we use a smooth log-power function which optimally fits experimental data and is infinitely differentiable. The partial moduli of the Maxwell chain from the log-power function make analysis easy because they change more smoothly in a more stable way than the ordinary method such as the least square method. Using the developed method, we can simulates the static crack growth test results satisfactorily.

• International Journal of Aeronautical and Space Sciences
• /
• v.13 no.4
• /
• pp.458-467
• /
• 2012

In this study, the linear viscoelastic response of a rectangular laminated plate is investigated. The viscoelastic properties, expressed by two basic spring-dashpot models, that is Kelvin and Maxwell models, is assumed in the range to investigate the influence of viscoelastic coefficients to mechanical behavior. In the present study, viscoelastic responses are performed for two popular equivalent single-layered theories, such as the first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT). Compliance and relaxation modulus of time-dependent viscoelastic behavior are approximately determined by Prony series. The constitutive equation for linear viscoelastic material as the Boltzmann superposition integral equation is simplified by the convolution theorem of Laplace transformation to avoid direct time integration as well as to improve both accuracy and computational efficiency. The viscoelastic responses of composite laminates in the real time domain are obtained by applying the inverse Laplace transformation. The numerical results of viscoelastic phenomena such as creep, cyclic creep and recovery creep are presented.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.41 no.4
• /
• pp.101-112
• /
• 2004

In this paper, we developed a numerical analysis model by using ADI-FDTD method to analyze three-dimensional interconnect structure. We discretized maxwell's curl equation by using ADI-FDTD. Using ADI-FDTD method, a sampler circuit designed from 3.3 V CMOS technology is simplified to 3-metal line structure. Using this simplified structure, the time delay and signal distortion of complex interconnects are investigated. As results of simulation, 5∼10 ps of delay time and 0.1∼0.2 V of signal distortion are measured. As demonstrated in this paper, the full-wave analysis using ADI-FDTD exhibits a promise for accurate modeling of electromagnetic phenomena in high-speed VLSI interconnect.