• Title/Summary/Keyword: equivalent force

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Analysis of Radial Force Density as a Vibration Source in Brushless DC Motor Using 3D Equivalent Magnetic Circuit Network Method (3차원 등가자기회로망법을 이용한 Brushless DC 모터의 진동원으로서의 Radial Force Density 해석)

  • Chun, Y.D.;Hur, J.;Yoon, S.B.;Hong, J.P.;Hyun, D.S.
    • Proceedings of the KIEE Conference
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    • 1997.07a
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    • pp.171-173
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    • 1997
  • This paper presents analysis of the radial force density in brushless DC motor of which distribution is not uniform in the axial direction. The analysis considering 3D shape of teeth and overhang is not only important but essential to calculate the radial force density that acts on the teeth of stator, because it is frequent source of vibration and changes at the end of teeth. For the analysis, a new 3D equivalent magnetic circuit network method taking into account movement of the rotor without remesh is proposed. The radial force density is calculated by Maxwell stress tensor and analyzed by discrete Fourier transform.

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Analysis on the Levitation Force Characteristics of Longitudinal Flux Type Levitation Magnet using Equivalent Magnetic Circuit Model (등가자기회로 모델을 이용한 종자속형 자기부상 전자석의 부상력 특성 해석)

  • Cho, Han-Wook;Kim, Chang-Hyun;Lee, Jong-Min;Han, Hyung-Suk
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.12
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    • pp.2236-2245
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    • 2011
  • This paper deals with the levitation force characteristics of electromagnet for MAGLEV vehicle application. The magnetic flux density distribution and levitation force characteristics of the electromagnet are investigated by means of equivalent magnetic circuit model. Firstly, we defined the aligned and unaligned electromagnet module for the full-electromagnet, and magnetic flux paths are represented for each model including leakage and fringing flux paths. Because of the analysis model contains both the permanent magnet and electromagnet coil, we calculated the airgap magnetic flux density and levitation forces using flux superposition in electromagnetic circuit. The results are validated extensively by comparison with finite element analysis. Moreover, the 1/4 scaled magnetic levitation and propulsion test vehicle has been manufactured and tested in order to verify these predictions. The experimental results confirms the validity of the analytical prediction with equivalent magnetic circuit model for the description of a electromagnet.

Determination of equivalent blasting load considering millisecond delay effect

  • Song, Zhan-Ping;Li, Shi-Hao;Wang, Jun-Bao;Sun, Zhi-Yuan;Liu, Jing;Chang, Yu-Zhen
    • Geomechanics and Engineering
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    • v.15 no.2
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    • pp.745-754
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    • 2018
  • In the analysis of the effects of rock tunnel blasting vibration on adjacent existing buildings, the model of simplified equivalent load produces higher calculation result of vibration, due to the lack of consideration of the millisecond delay effect. This paper, based on the static force equivalence principle of blasting load, proposes a new determination method of equivalent load of blasting vibration. The proposed method, based on the elastic-static force equivalence principle of stress wave, equals the blasting loads of several single blastholes in the same section of millisecond blasting to the triangle blasting load curve of the exploded equivalent elastic boundary surface. According to the attenuation law of stress wave, the attenuated equivalent triangle blasting load curve of the equivalent elastic boundary is applied on the tunnel excavation contour surface, obtaining the final applied equivalent load. Taking the millisecond delay time of different sections into account, the time-history curve of equivalent load of the whole section applied on the tunnel excavation contour surface can be obtained. Based on Sailing Tunnel with small spacing on Sanmenxia-Xichuan Expressway, an analysis on the blasting vibration response of the later and early stages of the tunnel construction is carried out through numerical simulation using the proposed equivalent load model considering millisecond delay effect and the simplified equivalent triangle load curve model respectively. The analysis of the numerical results comparing with the field monitoring ones shows that the calculation results obtained from the proposed equivalent load model are closer to the measured ones and more feasible.

The Shear and Friction characteristics Analysis of Inconel 718 End-millingIusing Equivalent Oblique Cutting System -Up endmilling- (등가경사절삭 시스템에 의한 Inconel 718 앤드밀링 공정의 전단 및 마찰특성 해석I -상향 엔드밀링-)

  • 이영문;최원식;송태성
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2001.04a
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    • pp.887-890
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    • 2001
  • In end milling process the underformed chip thickness and the cutting force components very periodically with phase change of the tool. In this study, up end milling process is transformed to the equivalent oblique cutting. The varying underformed chip thickness and the cutting force components in end milling process are replaced with the equivalent average ones. Then it can be possible to analyze the chip-tool friction and shear process in the shear plane of the end milling process by the equivalent oblique cutting mode. According to this analysis, when cutting Inconel 718.61% of the total energy is consumed in the shear process and the balance is consumed in the friction process.

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Analysis of the Up End Milling Process by Transforming to the Equivalent Oblique Cutting Model (경사절삭 모델에 의한 상향 엔드밀링절삭 해석)

  • 이영문;송태성;심보경
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2000.05a
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    • pp.902-906
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    • 2000
  • In end milling process the undeformed chip thickness and the cutting force components vary periodically with phase change of the tool. In this study, up end milling process is transformed to the equivalent oblique cutting. The varying undeformed chip thickness and the cutting force components in end milling process are replaced with the equivalent average ones. Then it can be possible to analyze the chip-tool friction and shear process in the shear plane of the end milling process by the equivalent oblique cutting model. According to this analysis, when cutting SM45C steel. 82% of the total energy is consumed in the shear process and the balance is consumed in the friction process.

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A Study on the Vibration Characteristics of Linear Stepping Motor using FEM and ACSL (유한요소법과 ACSL을 이용한 Linear Stepping Motor의 진동특성에 관한 연구)

  • Lee, Sang-Ho;Kim, Jung-Ki;Oh, Hong-Seok
    • Journal of the Korean Society of Industry Convergence
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    • v.6 no.2
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    • pp.141-147
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    • 2003
  • In this paper, the vibration characteristics of a linear stepping motor(LSM) are analyzed using the finite element method(FEM : Flux2D) and ACSL. A magnetic equivalent circuit is based on the structure of the LSM, and then the electric equivalent circuit of the LSM is derived by solving equations for the magnetic equivalent circuit. A normal force is calculated using FEM. And the vibration characteristics of the LSM are simulated by the ACSL with the voltage equations, the thrust equations, the normal force equations and the kinetic equations, and are measured by LASER experimental system.

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Response Reduction of a SDOF Structure based on Friction Force Ratio of MR Controller (MR제어기의 마찰력비에 따른 단자유도 구조물의 응답감소)

  • Seong, Ji-Young;Min, Kyung-Won
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.4
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    • pp.435-443
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    • 2010
  • This study presents key parameters for the structure installed with MR controller in reducing its responses. MR controller is regarded as Bingham model of which control forces are frictional and viscous ones. The parameters are identified as friction force ratios, $R_f$ and $R_h$ which are, respectively, ratio of MR controller friction force to static restoring force for free vibration and ratio of the friction force to amplitude of harmonic force. Structure-MR controller system shows nonlinear response behavior due to friction force. Energy balance strategy is adopted to transform the behavior to linear one with equivalent damping ratio. Finally, proposed equivalent linear process is compared to the nonlinear one, which turns out to give acceptably good results.

A Study of the Iron-Core Solenoid Analysis for 3 D.O.F. Motor Control with Experimental Method (3자유도 모터 제어를 위한 철심 솔레노이드 특성의 실험적 해석에 관한 연구)

  • Baek, Yoon-Su;Park, Joon-Hyuk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.9
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    • pp.1334-1340
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    • 2001
  • In this paper, the experimental modeling of the force between permanent magnet and iron-core solenoid is suggested for more accurate control of 3 D.O.F. motor using the electromagnetic force. In the case of iron-core solenoid, the general equation of solenoid cant be used simply because of its nonlinearity. Therefore, the magnetic flux density is estimated through the concept of equivalent permanent magnet. The force distribution between permanent magnet and iron-core solenoid is more dependent on the magnetization of iron core caused by the permanent magnet than any other parameters. Therefore, the equation of the force estimation between these magnetic systems can be modeled by the experimental function of the magnetization of iron core. Especially, if the distance between iron-core solenoid and permanent magnet is far enough, the force equation through experiment can be expressed from only the current of coil and the distance between iron-core solenoid and permanent magnet. It means that Coulombs law can be used for magnetic systems and it is validated through the experiment. Therefore, force calibration is performed by the concept of Coulombs law.

Study on Structural Safety of Automotive Inner and Outer Bumper (차체 안쪽과 바깥쪽 범퍼의 구조 안전성에 관한 연구)

  • Han, Moon-Sik;Cho, Jae-Ung
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.2
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    • pp.130-134
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    • 2011
  • This study aims at the structural safety with optimum design of automotive bumper in order to minimize the maximum stress and displacement and reduce the minimum quantity of bumper material. As the forces of X and Y direction increase, equivalent stress and displacement increase. The displacement of X direction force increases more than 20% in comparison with Y direction force. But the equivalent stress of Y direction force increases more than 60% in comparison with X direction force. The mass of inner bumper becomes minimum and the mass of outer bumper becomes maximum when the force of 4000N is applied on the direction inclined at $45^{\circ}$ toward outer bumper. In 50% range of increase and decrease at X and Y direction force, the optimum forces of X and Y component becomes 2368.8N and 1538.8N respectively. And the masses of inner and outer polypropylene bumper become $3.3227{\times}10^{-2}kg$and $3.5538{\times}10^{-2}kg$respectively.

Modified nonlinear force density method for form-finding of membrane SAR antenna

  • Xu, Rui;Li, DongXu;Liu, Wang;Jiang, JianPing;Liao, YiHuan;Wang, Jie
    • Structural Engineering and Mechanics
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    • v.54 no.6
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    • pp.1045-1059
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    • 2015
  • Form-finding for cable-membrane structures is a delicate operation. During the last decades, the force density method (FDM) was considered to be an efficient method to address the problem. Many researchers were devoted to improving this method and proposed many methods such as natural force density method (NFDM), improved nonlinear force density method (INFDM), et al. In this paper, a modified nonlinear force density method (MNFDM) is proposed. In this method, the stresses of membrane elements were transformed to the force-densities of cable nets by an equivalent relationship, and then they can be used as initial conditions. By comparing with the forming finding results by using the FDM, NFDM, INFDM and MNFDM, it had demonstrated that the MNFDM presented in this paper is the most efficient and precise.