• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.3
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• pp.208-213
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• 2012

With great advancement of the automobile functions, environmental factors become important performances, especially noise. This paper investigates noise sources of outer rotor type BLDC motor using in the air-conditioner of the automobiles. To this end, this paper is analyzed two viewpoints, structural and electromagnetic causes. Structural analysis is conducted through modal test and analysis. For modal analysis, 3D finite element analysis is carried out using commercial program ansys. Electromagnetic causes are analyzed from local force that is computed by Maxwell stress tensor method. Local force excites structure of motor directly. Finally, correlation analysis is performed to determine effect between noise causes.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.79-80
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• 2006

From a viewpoint of heat stress at high temperatures and contact thermal resistance, it is confirmed that the optimal structure is the skeleton structure using Cu substrate on the cooling side, which has excellent heat conductivity and the optimal installation method is to adopt a carbon sheet and a mica sheet to the high temperature side, where Si grease is applied to the low temperature side, under pressurized condition. The power of the developed modules indicated 0.5W in an $FeSi_2$ module and 3.8 W with a SiGe module at 823K, respectively.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.7
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• pp.591-598
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• 2011

This paper presents dynamic analysis of FCEV(fuel cell electric vehicle) turbo blower. To analyze the dynamic characteristics of turbo blower, FEA(finite element analysis) and experimental test are performed. Evaluations of stress safety for rotor sleeve and impeller due to rotational force and shrink fit are performed. Rotor dynamic analysis is conducted by Campbell diagram and structure vibration analyses are performed using FEA and experimental test. Through these results, noise sources of turbo blower are verified.

• Structural Engineering and Mechanics
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• v.70 no.2
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• pp.245-255
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• 2019

In present research, we have considered transversely isotropic magneto thermoelastic solid with two temperature and without energy dissipation due to inclined load. The mathematical model has been formulated using Lord-Shulman theory. The Laplace and Fourier transform techniques have been used to find the solution to the problem. The displacement components, stress components and conductive temperature distribution with the horizontal distance are computed in the transformed domain and further calculated in the physical domain using numerical inversion techniques. The effect of rotation and angle of inclination of inclined load is depicted graphically on the resulting quantities.

• Proceedings of the KIEE Conference
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• 2007.10c
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• pp.118-120
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• 2007

This paper deals with the vibration analysis of characteristics for BLDC motor by electromagnetic exciting force. Vibration analysis of electric machine is mainly divided into mechanical and electrical approach. However, it need to execute coupling analysis of mechanical and electrical computation because the vibration sources have relation to each other. Magnetic fields is calculated from Maxwell stress method with electromagnetic finite element method. And magnetic radial force is calculated from previous magnetic fields. With coupled electromagnetic and structure finite element, the vibratory behavior between the phase commutation advancing technique and pulse-width control is investigated in single phase brushless dc motor.

• Geomechanics and Engineering
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• v.19 no.4
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• pp.295-305
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• 2019

The present paper is concerned with the investigation of disturbances in orthotropic thermoelastic medium by using fractional order heat conduction equation with three phase lags due to thermomechanical sources. Laplace and Fourier transform techniques are used to solve the problem. The expressions for displacement components, stress components and temperature change are derived in transformed domain and further in physical domain using numerical inversion techniques. The effect of fractional parameter based on its conductivity i.e., ($0<{\alpha}<1$ for weak, ${\alpha}=1$ for normal, $1<{\alpha}{\leq}2$ for strong conductivity) is depicted graphically on various components.

• Structural Engineering and Mechanics
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• v.77 no.3
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• pp.315-327
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• 2021

Here, in this research we have studied a two dimensional problem in a homogeneous orthotropic magneto-thermoelastic medium with higher order dual-phase-lag heat transfer with combined effects of rotation and hall current in generalized thermoelasticity due to time harmonic sources. As an application the bounding surface is subjected to uniformly distributed and concentrated loads (mechanical and thermal source). Fourier transform technique is used to solve the problem. The expressions for displacement components, stress components and temperature change are derived in frequency domain. Numerical inversion technique has been used to obtain the results in physical domain. The effect of frequency has been depicted with the help of graphs.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.55.3-55.3
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• 2018

Magnetars are neutron stars powered by strong magnetic field (B > $10^{14}G$). Their spin period is in the range of 2 - 12s. The magnetic stress in the star may distort the crust (observed as outbursts), so magnetars (especially in outbursts) may emit gravitational waves. There are 29 magnetars known (potential gravitational waves sources), and increasing the number will increase the chance of detecting low-frequency gravitational waves. In addition, magnetars can be used for studying matter under extreme condition. In this study, we searched for more magnetars using extensive Chandra archival data and found 11 candidates. Due to the limited sensitivity of Chandra, form identification cannot be made, and more sensitivity X-ray data are needed.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.1001-1003
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• 1993

Steep-fronted surges associated with motor witching cause relatively large turn-to-turn winding stress. In order to calculate the surge level at the motor terminals, equivalent circuits consist of three parts with power sources, load cable and motor constants. This paper presents switching surges phenomena occurred in a high voltgae induction motor witching by EMTP.

• Advances in materials Research
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• v.8 no.2
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• pp.83-102
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• 2019

The present research deals with the time harmonic deformation in transversely isotropic magneto thermoelastic solid with two temperature (2T), rotation and without energy dissipation due to inclined load. Lord-Shulman theory has been formulated for this mathematical model. The entire thermo-elastic medium is rotating with a uniform angular velocity. The Fourier transform techniques have been used to find the solution to the problem. The displacement components, stress components and conductive temperature distribution with the horizontal distance are computed in the transformed domain and further calculated in the physical domain using numerical inversion techniques. The effect of time harmonic source and rotation is depicted graphically on the resulting quantities.