• Title/Summary/Keyword: equivalent force

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Stress Analysis with respect to the change of the Shape of Screw Blade and the Hole for Centrifuge (원심분리기용 스크류의 블레이드 및 원공형상변화에 따른 음력해석)

  • 이성욱;심재준;한동섭;한근조;안찬우;김태형
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.749-752
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    • 2002
  • In this study, we carried out the finite element analysis about screw that is the weakest part of the centrifuge for sewage management. Structural analysis was done with respect to the change of outer radius and thickness of screw blade and screw with sewage discharge hole. If the area of circular hole is equal to that of extended holes, maximum equivalent stress was compared between hole and extended hole. Centrifugal force on account of rotation of 4000 rpm was applied the screw. The results are as follows : 1 . When the larger radius and thickness of screw blade was used, the higher maximum equivalent stress is occurred. 2. When the larger radius of sewage discharge hale was used, the higher maximum equivalent stress is occurred. 3. When the longer parallel part length of extended hole was used, the higher maximum equivalent stress is occurred. 4. If the extended hole with the same discharging area which circular hole uses, the maximum equivalent stress is lower.

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Determination of the Static Rigidity of the End Mill Using Neural Network (신경망을 이용한 엔드밀의 정적 강성 결정)

  • Lee, Sang-Kyu;Ko, Sung-Lim
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.12
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    • pp.143-152
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    • 1997
  • The deflection of an end mill is very important in machining process and cutting simulation because it affects directly workpiece accuracy, cutting force, and chattering. In this study, the deflection of the end mill was studied both experimentally and by using finite element analysis. And the moment of inertia of cross sections of the helical end mill is calculated for the determination of the relation between geometry of radial cross section and rigidity of the tools. Using the Bernoulli-Euler beam theory and the concept of equivalent diameter, a deflection model is established, which includes most influences from tool geomety parameters. It was found that helix angle attenuates the rigidity of the end mill by the finite element analysis. As a result, the equivalent diameter is determined by tooth number, inscribed diameter ratio, cross sectional geometry and helix angle. Because the relation betweem equivalent diameter and each factor is nonlinear, neural network is used to decide the equivalent diameter. Input patterns and desired outputs for the neural network are obtained by FEM analysis in several case of end milling operations.

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Development of the Design Algorithm Using the Equivalent Magnetic Circuit Method for Colenoid Type Electromagnetic Linear Actuator (등가자기회로를 활용한 콜레노이드 타입 선형 액츄에이터 설계 알고리즘 개발)

  • Han, Dong-Ki;Chang, Jung-Hwan
    • Journal of the Korean Magnetics Society
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    • v.26 no.2
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    • pp.55-61
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    • 2016
  • This study proposes the design algorithm of an electromagnetic linear actuator with a divided coil excitation system, such as the colenoid (COL) system, using the equivalent magnetic circuit (EMC) method. Nowadays, the clamping device is used to hold workpiece in the electrically driven chucking system and is needed to produce a huge clamping force of 40 kN like hydraulic system. The design algorithm for electromagnetic linear actuator can be obtained using the EMC method. At first, the parameter map is used to decide the slot width ratio in the initial design. Next, to make the magnetic flux density uniform at each pole, the pole width is adjusted by the pole width adjusting algorithm with EMC. When the dimensions of the electromagnetic linear actuator are decided, the clamping force is calculated to check the desired clamping force. The design results show that it can be used to hold a workpiece firmly instead of using a hydraulic cylinder in a chucking system.

Study on Hot Spot Stress Calculation for Welded Joints using 3D Solid Finite Elements (3차원 솔리드 요소를 이용한 용접부 핫스팟 응력 계산에 대한 연구)

  • Oh, Jung-Sik;Kim, Yooil;Jeon, Seok-Hee
    • Journal of Ocean Engineering and Technology
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    • v.29 no.1
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    • pp.45-55
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    • 2015
  • Because of the high stress concentration near the toe of a welded joint, the calculation of local stress using the finite element method which is relevant to the fatigue strength of the weld toe crack, is a challenging task. This is mainly caused by the sensitivity of finite element analysis, which usually occurs near the area of a dramatically changing stress field. This paper presents a novel numerical method through which a less mesh-sensitive local stress calculation can be achieved based on the 3D solid finite element, strictly sticking to the original definition of hot spot stress. In order to achieve the goal, a traction stress, defined at 0.5t and 1.5t away from the weld toe, was calculated using either a force-equivalent or work-equivalent approach, both of which are based on the internal nodal forces on the imaginary cut planes. In the force-equivalent approach, the traction stress on the imaginary cut plane was calculated using the simple force and moment equilibrium, whereas the equivalence of the work done by both the nodal forces and linearized traction stress was employed in the work-equivalent approach. In order to confirm the validity of the proposed method, five typical welded joints widely used in ships and offshore structures were analyzed using five different solid element types and four different mesh sizes. Finally, the performance of the proposed method was compared with that of the traditionally used surface stress extrapolation method. It turned out that the sensitivity of the hot spot stress for the analyzed typical welded joints obtained from the proposed method outperformed the traditional extrapolation method by far.

Novel Design and Research for a High-retaining-force, Bi-directional, Electromagnetic Valve Actuator with Double-layer Permanent Magnets

  • You, Jiaxin;Zhang, Kun;Zhu, Zhengwei;Liang, Huimin
    • Journal of Magnetics
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    • v.21 no.1
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    • pp.65-71
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    • 2016
  • To increase the retaining force, a novel design for a concentric, bi-directional, electromagnetic valve actuator that contains double-layer permanent magnets is presented in this paper. To analyze the retaining-force change caused by the magnets, an equivalent magnetic circuit (EMC) model is established, while the EMC circuit of a double-layer permanent-magnet valve actuator (DLMVA) is also designed. Based on a 3D finite element method (FEM), the calculation model is built for the optimization of the key DLMVA parameters, and the valve-actuator optimization results are adopted for the improvement of the DLMVA design. A prototype actuator is manufactured, and the corresponding test results show that the actuator satisfies the requirements of a high retaining force under a volume limitation; furthermore, the design of the permanent magnets in the DLMVA allow for the attainment of both a high initial output force and a retaining force of more than 100 N.

Analysis of 3-D Cutting Process with Single Point Tool

  • Lee, Young-Moon;Park, Won-Sik;Song, Tae-Seong
    • International Journal of Precision Engineering and Manufacturing
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    • v.1 no.1
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    • pp.15-21
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    • 2000
  • This study presents a procedure for analyzing chip-tool friction and shear processes in 3-D cutting with a single point tool. The edge of a single point tool including a circular nose is modified to an equivalent straight edge, thereby reducing the 3-D cutting with a single point tool to the equivalent of oblique cutting. Then, by transforming the conventional coordinate systems and using the measurements of three cutting force components, the force components on the rake face and shear plane of the equivalent oblique cutting system can be obtained. As a result, the chip-tool friction and shear characteristics of 3-D cutting with a single point tool can be assessed.

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The Shear and Friction characteristics Analysis of End-milling (엔드밀링의 전단특성 및 마찰특성 해석)

  • Lee, Y.M.;Song, T.S.;Shim, B.K.
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.724-729
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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, 72% of the total energy is consumed in the shear process and the balance is consumed in the friction process.

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The Shear and Friction Characteristics Analysis of End-Milling (엔드밀링의 전단특성 및 마찰특성 해석)

  • Lee, Yeong-Mun;Song, Tae-Seong;Sim, Bo-Gyeong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.10
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    • pp.1520-1527
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    • 2001
  • 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, 72% of the total energy is consumed in the shear process and the balance is consumed in the friction process.

Application of Equivalent Drawbead Model to Auto-Body Stamping Analysis (차체 스탬핑 해석에 등가 드로우비드 모델의 적용)

  • Lee, J.Y.;Moon, S.J.;Keum, Y.T.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.05a
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    • pp.389-392
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    • 2009
  • The application of an equivalent drawbead model(EDM) for sheet metal forming analysis, which adopts the forces instead of complex geometries in modeling the drawbead, to the numerical simulation of auto-panel stamping process is introduced in this study. In terms of the thinning and draw-in, better agreement with experimental measurements was found in EDM than in commercial code models so that the excellence of EDM in the accuracy of drawbead forces for the simulation of auto-body stampings was revealed.

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A Study on the vibration analysis of 2-phase HB type Linear Stepping Motor using ACSL (ACSL에 의한 2상 HB형 선형 STEPPING 전동기의 진동해석에 관한 연구)

  • Oh H.S;Jung E.N;Lee S.H;Lee B.S;Won K.S;Kim J.K
    • Proceedings of the KIPE Conference
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    • 2001.07a
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    • pp.14-17
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    • 2001
  • In this paper, the vibration characteristics of a 2-phase Hybrid type Linear Stepping Motor(HLSM) are analyzed using the ACSL. A magnetic equivalent circuit is based on the structure of the HLSM, and then the electric equivalent circuit of the HLSM is derived by solving equations for the magnetic equivalent circuit. A normal force is calculated using FEM(Flux2D). And the vibration characteristics of the HLSM are simulated by the ACSL with the voltage equations, the thrust equation, the normal force equation and the kinetic equation.

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