• Title/Summary/Keyword: Power Flow Finite Element Method

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Development of Sound Radiation Analysis System Using the Results of Power Flow Finite Element Method (파워흐름유한요소법의 진동해석 결과를 이용한 구조물의 방사소음 해석시스템 개발)

  • 이호원;홍석윤
    • The Journal of the Acoustical Society of Korea
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    • v.20 no.7
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    • pp.21-30
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    • 2001
  • The analysis system implementing a serial process from structural vibration to sound radiation has been developed using both the power flow finite element method (PFFEM) known as a new vibrational analysis technique in medium to high frequency ranges and the acoustic boundary element method (BEM) which is effective in analyzing the sound radiation problems. The vibration analysis for arbitrary shape structures composed of plates is performed, and using the vibration energy density obtained from this analysis as the velocity boundary conditions for an acoustic analysis, vibro-acoustic analysis has been processed. To verify the developed system, we select a simple structure model and compare the results of developed system with those of SYSNOISE, and also the developed system is applied for the vibro-acoustic analysis of various structures in shapes.

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Development of Vibration Analysis Software, PFADS-R3 using Power Flow Analysis (파워흐름해석법을 이용한 진동해석 소프트웨어, PFADS-R3 개발)

  • 홍석윤;서성훈;박영호;길현권
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.11a
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    • pp.824-830
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    • 2003
  • The Power Flow Finite Element Method(PFFEM) offers very promising results in predicting the vibration responses of system structures, and the first PFFEM software, PFADS has been developed in Seoul National University for the vibration predictions and analysis of coupled system structures in medium-to-high frequency ranges. PFFEM is numerical method which solves energy governing equation using finite element technique for complicated structures where the exact solutions are not available. Through the upgrades, the current version PFADS R3 could cover the general beam and plate structures including various kinds of beam-plate rigid joints, spring-damper connection and rigid body connection within beam and plate in addition. This software is composed of three parts; translator, model converter and solver. The translator makes its own FE-model from bulk data of commercial FE software, and the model converter is used to convert FE-model to PFFE-model automatically. The solver calculates vibrational energy density and intensity for PFFE-model by solving global matrix equations of PFFEM. For the applications of PFADS R3, two vehicle models and a container model are examined with respect to major parameters, and reliable results are obtained.

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A Study on Vibration Power Flow of 2-Dimension Structure Travelling from the Source (진동원으로부터 전달되는 2차원 구조물의 진동파워흐름에 관한 연구)

  • 노영희;김동영;홍도관;권용수;안찬우;한근조
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.879-882
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    • 2002
  • To control the vibration and sound of structure, it is important to analyze the dynamic action of structure. And through those analysis, the vibration source and the flow path is understood. To grasp that, when the two-dimension plate structure is shaken by a harmonic point excitation with the natural frequency using the finite element method, this paper presents the relation between vibration power flow and mode shape. As those results present to vector flow, the vibration power flow is visualized.

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A Study on Vibration Power Flow of Truss Core Type Sandwich Plate Structure (트러스코어형 샌드위치 판구조물의 진동파워흐름에 관한 연구)

  • 구경민;김동영;홍도관;박일수;안찬우;한근조
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.863-866
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    • 2002
  • In this study, we tried to grasp the characteristic of vibration power flow for the truss core type sandwich plate structure. As the result of the finite element analysis, this paper shows that the vibration power flow characteristic of truss core type sandwich plate structure is understood and the vibration power flow of upper plate according to the mode shape of structure is various. Also it presents the vibration power flow is affected by reinforced structure.

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Research on Vibro-acoustic Coupled Analysis using Power Flow Finite Element Method (파워흐름유한요소법을 이용한 진동음향 연성해석 연구)

  • Kim, Sung-Hee;Kwon, Hyun-Wung;Hong, Suk-Yoon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.11a
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    • pp.767-770
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    • 2006
  • To predict vibrational energy density of simple structural-acoustic coupled systems in medium-to-high frequency ranges, Power Flow Finite Element Method(PFFEM) is used, and PFFEM sofiware, PFADS has been developed for the vibration predictions and analysis of coupled system structures in medium-to-high frequency ranges. However, it needs to consider vibro-acoustic coupled analysis to get more accurate results. Prior to implement vibro-acoustic coupled analysis functions in PFADS, research on vibro-acoustic coupled analysis using PFFEH is performed for simple models. These predictions include the indirect transmission path associated, and also the direct transmission path, and the formulation is extended to structural system model by using appropriate modifications to structural-acoustic and acoustic-acoustic joint matrices. Concerning the waves in plate and acoustic, it is possible to calculate the structural-acoustic full matrix of a model using PFFEM, and the formulations developed are implemented for two rooms surrounded by plates.

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Comparison on the Forming Force of Flow Forming with Various Roller Profiles (다양한 롤러 단면형상을 적용한 유동성형의 성형력 비교)

  • Nam, Kyoung-O;Kim, Bum-Nyun;Won, Jong-Ho
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.4
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    • pp.113-118
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    • 2007
  • The flow forming has been used to produce long thin walled tube parts, with the reduced fanning force and the enhanced mechanical and surface quality for a good finished part, compared with the fanned parts using other method. Therefore, flow fanning technique is used widely in industrial production. Spinning and flow fanning techniques are used frequently in automotive, aerial and defense industries. The main factors for the flow fanning machine design are motor power, bed rigidity, mandrel stiffness, spindle power, roller profile, etc. Especially, mandrel, spindle power and roller are important factors for flow fanning machine capacity. In this paper, three dimensional finite element method for analysis of one-roller backward flow fanning of a workpiece has been carried out to study effects of roller profile on fanning force. Applied roller profile have roller lead geometries of angle $20^{\circ},\;30^{\circ},\;40^{\circ}$, concave and convex. Axial and radial fanning forces on various roller profiles are obtained and compared with each analysis cases.

Experimental Study on Power Flow Analysis of Vibration of an Automobile Door (자동차 도어 진동의 파워흐름해석에 대한 실험적 연구)

  • Kil, H.G.;Lee, Y.H.;Lee, G.H.;Hwang, S.G.;Hong, S.Y.;Park, Y.H.;Seo, J.K.;Chae, G.S.;Seo, S.H.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.782-785
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    • 2006
  • The Power Flow Analysis(PFA) can be effectively used to predict structural vibration in medium-to-high frequency range. In this paper, Power Flow Finite Element Method (PFFEM) based on PFA has been used to predict the vibration of an automobile door. The predicted results for the frequency response function of the door have been compared with corresponding experimental results. In the experiment, the automobile door has been divided into several subsystems and the loss factor of each subsystem has been measured. The input mobility at a source point has been also measured. The data for the loss factors and the input mobility have been used as the input data to predict the vibration of the automobile door with PFFEM. The frequency response functions have been measured over the surface of the door. The comparison between the experimental results and the predicted results for the frequency response functions showed that PFFEM could be an effective tool to predict the structural vibration.

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Vibration Intensity Analysis of Penetration Beam-plate Coupled Structures (관통보와 평판의 연결 구조물에 대한 진동인텐시티 해석)

  • 홍석윤;강연식
    • The Journal of the Acoustical Society of Korea
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    • v.21 no.1
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    • pp.73-81
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    • 2002
  • The transmission of vibration energy through beam-plate junctions in vibration intensity analysis called power new analysis (PFA) has been studied. PFA is an analytic tool for the prediction of frequency averaged vibration response of built-up structures at medium to high frequency ranges. The power transmission and reflection coefficients between the semi-infinite beam and plate are estimated using the wave transmission approach. For the application of the power coefficients to practical complex structures, the numerical methods, such as finite element method are needed to be adapted to the power flow governing equation. To solve the discontinuity of energy density at the joint, joint matrix is developed using energy flow coupling relationships at the beam-plate joint. Using the joint matrix developed in this paper, an idealized ship stem part is modeled with finite element program, and vibration energy density and intensity are calculated.

Analysis of Two-Dimensional Fretting Wear Using Substructure Method (부분구조법을 이용한 2차원 프레팅 마모 해석)

  • Bae, Joon-Woo;Chai, Young-Suck;Lee, Choon-Yeol
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.7 s.262
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    • pp.784-791
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    • 2007
  • Fretting, which is a special type of wear, is defined as small amplitude tangential oscillation along the contacting interface between two materials. In nuclear power plants, fretting wear caused by flow induced vibration (FIV) can make a serious problem in a U-tube bundle in steam generator. In this study, substructure method is developed and is verified the feasibility for the finite element model of fretting wear problems. This method is applied to the two-dimensional finite element analyses, which simulate the contact behavior of actual tube to support. For these examples, computing time can be reduced up to 1/5 in comparisons with conventional finite element analyses.

Determination of Flow Stress and Friction Factor by the Ring Compression Test (II) (링압축실험에 의한 유동응력 및 마찰인자의 결정 (II))

  • 최영민;김낙수
    • Transactions of Materials Processing
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    • v.3 no.2
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    • pp.215-228
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    • 1994
  • The purpose of this paper is to pursue a general method to determine both the flow stress of a material and the friction factor by ring compression test. The materials are assumed to obey the expanded n-power hardening rule including the strain-rate effect. Ring compression is simulated by the rigid-plastic finite element method to obtain the database used in determining the flow stress and friction factor. The Simulation is conducted for various strain hardening exponent, strain-rate sensitivity, friction factor, and compressing speed, as variables. It is assumed that the friction factor is constant during the compression process. To evaluate the compatibility of the database, experiments are carried out at room and evaluated temperature using specimens of aluminum 6061-T6 under dry and grease lubrication condition. It is shown that the proposed test method is useful and easy to use in determining the flow stress and the friction factor.

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