• 한국기계가공학회지
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• 제21권9호
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• pp.85-91
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• 2022

The demand for electric vehicles has increased because of environmental regulations. The lithium-ion battery, the most widely used type of battery in electric vehicles, is composed of a cathode, an anode, and an electrolyte. It is manufactured according to the pole plate, assembly, and formation processes. To improve battery performance and increase manufacturing efficiency, the manufacturing process must be optimized. To do so, simulation can be used to reduce wasted resources and time, and a finite-element method can be utilized. For high simulation quality, it is essential to reflect the material properties of the electrode by considering the pores. However, the material properties of electrodes are difficult to derive through measurement. In this study, the representative volume element method, which is a homogenization method, was applied to estimate the representative material properties of the electrode considering the pores. The representative volume element method assumes that the strain energy before and after the conversion into a representative volume is conserved. The method can be converted into one representative property, even when nonhomogeneous materials are mixed in a unit volume. In this study, the material properties of the electrode considering the pores were derived. The results should be helpful in optimizing the electrode manufacturing process and related element technologies.

• Structural Engineering and Mechanics
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• 제62권5호
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• pp.519-535
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• 2017

In this article, static analysis of a magneto-electro-elastic (MEE) beam subjected to various thermal loading and boundary conditions has been investigated. Influence of pyroeffects (pyroelectric and pyromagnetic) on the direct quantities (displacements and the potentials) of the MEE beam under different boundary conditions is studied. The finite element (FE) formulation of the MEE beam is developed using the total potential energy principle and the constitutive equations of the MEE material taking into account the coupling between elastic, electric, magnetic and thermal properties. Using the Maxwell electrostatic and electromagnetic relations, variation of stresses, displacements, electric and magnetic potentials along the length of the MEE beam are investigated. Effect of volume fractions, aspect ratio and boundary conditions on the direct quantities in thermal environment has been determined. The present investigation may be useful in design and analysis of magnetoelectroelastic smart structures and sensor applications.

• Structural Engineering and Mechanics
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• 제63권4호
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• pp.481-495
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• 2017

The present article examines the static response of multilayered magneto-electro-elastic (MEE) beam in thermal environment through finite element (FE) methods. On the basis of the minimum total potential energy principle and the coupled constitutive equations of MEE material, the FE equilibrium equations of cantilever MEE beam is derived. Maxwell's equations are considered to establish the relation between electric field and electric potential; magnetic field and magnetic potential. A simple condensation approach is employed to solve the global FE equilibrium equations. Further, numerical evaluations are made to examine the influence of different in-plane and through-thickness temperature distributions on the multiphysics response of MEE beam. A parametric study is performed to evaluate the effect of stacking sequence and different temperature profiles on the direct and derived quantities of MEE beam. It is believed that the results presented in this article serve as a benchmark for accurate design and analysis of the MEE smart structures in thermal applications.

• Journal of Power Electronics
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• 제6권2호
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• pp.163-171
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• 2006

In this paper, a Switched Reluctance Motor (SRM) employed in an electric vehicle (EV) is designed using the finite element method (FEM). The static torque of the SRM is estimated through magnetic field analysis. The SRM temperature rise over operation time is estimated through heat transfer analysis. First, static torque and temperature rise over the time of 600W SRM is included in the experiment set, and are compared with the calculated results using the FEM under the same conditions. The validity of the magnetic field analysis and heat transfer analysis is verified by the comparisons. In addition, a 60 [kW] SRM employed in an EV, whose output characteristics are equal to a 1500 [cc] gasoline engine, is designed under magnetic field analysis and heat transfer analysis.

• 수산해양기술연구
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• 제53권3호
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• pp.302-307
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• 2017

An electric steam boiler equipped with a condensate recovery system, which stores the condensate generated after using steam in steam washers, steam cookers, steam irons, and steam cleaners in a condensate tank and supplies compressed air to the condensate tank so that the condensate is recovered to the boiler by the pressure of the compressed air, was studied. In the results of this study, the heat energy balance between the quantity of the heat generated by the non-metallic surface heating element and the quantity of the heat absorbed by the water was good in a range of ${\pm}5%$. In addition, the heat transfer rate increased in proportion to the electric power of the surface heating element heater, the waste heat energy was normally recovered by the recovery of the condensate of the steam boiler equipped with the high compression waste heat recovery system, and the recovery rate of the waste heat exhibited 23%.

• 한국수소및신에너지학회논문집
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• 제23권1호
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• pp.100-109
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• 2012

In this paper, some ideas are proposed to establish the infrastructure of all-electric houses which are able to reduce primary energy consumption and $CO_2$ emission by adopting heat pump systems and induction heating cookers excluding the use of fossil fuel energy. This electrification concept is based on the consumption of only one type of energy which means electricity as secondary energy and the conventional fossil fuel energy is just consumed to generate electricity as primary energy. All-electric house is laid on the extension of the hydrogen economy in a long-term viewpoint so that the effectiveness of this new conceptual house is estimated analyzing the reduction of $CO_2$ emission. In this analysis, the balance of electricity supply and demand is considered including the construction of new power plants by renewable energy such as nuclear, IGCC and fuel cell because decarbonization is an essential element of hydrogen technology and economy and this action is accomplished in both supply and demand side of electricity. The results are able to contribute to develop various useful hydrogen policies and strategies and some detail researches are required previously to make the best application of this new conceptual house.

• 한국세라믹학회지
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• 제53권4호
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• pp.444-449
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• 2016

Industrial by-products generated by integrated iron and steel manufacture cause environmental pollution. The by-products contain not only iron element but also harmful substances. Therefore, in view of to waste recycling and environmental preservation, production of sponge iron using the by-product is considered an effective recycling method. In this study, reduction efficiency of pellets from blast furnace dust was measured. Metallization was found to be increased, as $C/Fe_{total}$ ratio and reaction time were increased. The pellets were formed into a globular shape, and calcined for 60 minutes at $1100^{\circ}C$ in an electric furnace. Phase changes were analyzed using an X-ray diffractometer. Microstructures of the pellets were observed by a scanning electron microscope.

• 반도체디스플레이기술학회지
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• 제22권3호
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• pp.21-27
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• 2023

In this article, a plate-type megasonic cleaning system with cooling pins is proposed for the sliced ingot, which is a raw material of silicon (Si) wafers. The megasonic system is operated with a lead zirconate titanate (PZT) actuator, which has high electric resistance, thus when it is being operated, it dissipates much heat. So this article proposes a megasonic system with cooling pins. In the design process, finite element analysis was performed and the results were used for the design of the waveguide. The frequency with the maximum impedance value was 998 kHz, which agreed well with the measured value of 997 kHz with 0.1 % error. Based on the results, the 1 MHz waveguide was fabricated. Acoustic pressures were measured, and analyzed. Finally, cleaning tests were performed, and 90 % particle removal efficiency (PRE) was achieved over 10 W power. These results imply that the developed 1 MHz megasonic will effectively clean sliced ingot wafer surfaces.

• 조명전기설비학회논문지
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• 제21권3호
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• pp.125-131
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• 2007

가전분야에서의 전동기 효율향상을 통한 에너지 소비절감 효과는 상당히 크지만 이를 위한 전동기의 설계/해석 기술 확보가 아직은 미흡한 상태이다. 이에 따라 유도형 동기전동기가 제안되었지만, 유도형 동기 전동기는 유도전동기와 통기전동기의 특성을 동시에 가지고 있어, 해석 및 설계가 쉽지 않다. 따라서 본 논문에서는 기존의 냉장고 압축기용 전동기인 단상유도전동기를 대처할 수 있는 단상 유도형 동기전동기를 이용해 파라미터에 따라 특성이 어떻게 바뀌는가에 대해 서술하였다. 그에 따라 단상유도전동기의 정상상태 특성을 해석하고 제안모델의 성능을 기존모델과 비교하고 실험하여 해석결과의 신뢰성을 검증한다. 또한 본 논문에서는 제안모델의 기존 고정자 형상이나 권선 스팩을 유지하고 회전자의 형상이나 구조만을 변경시켜 성능향상을 도모하였다. 해석방법으로는 전자장 수치 해석적인 방법으로 널리 이용되고 있는 유한요소법(Finite Element Method : FEM)을 이용하였다.

• Smart Structures and Systems
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• 제21권4호
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• pp.493-519
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• 2018

This article presents a finite element (FE) model to assess the free vibration and static response of a functionally graded skew magneto-electro-elastic (FGSMEE) plate. Through the thickness material grading of FGSMEE plate is achieved using power law distribution. The coupled constitutive equations along with the total potential energy approach are used to develop the FE model of FGSMEE plate. The transformation matrix is utilized in bringing out the element matrix corresponding to the global axis to a local axis along the skew edges to specify proper boundary conditions. The effect of skew angle on the natural frequency of an FGSMEE plate is analysed. Further, the study includes the evaluation of the static behavior of FGSMEE plate for various skew angles. The influence of skew angle on the primary quantities such as displacements, electric potential, and magnetic potential, and secondary quantities such as stresses, electric displacement and magnetic induction is studied in detail. In addition, the effect of power-law gradient, thickness ratio, boundary conditions and aspect ratio on the free vibration and static response characteristics of FGSMEE plate has been investigated.