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  • Title/Summary/Keyword: 진동물체

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Analysis of Dynamic Behaviors for the Korea High Speed Train(KHST) by Using Non-Linear Creep Theory (비선형 크립이론을 이용한 한국형 고속전철의 동특성 해석)

  • 박찬경;김석원;김회선
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.1093-1098
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    • 2002
  • Dynamic behaviors of the Korean High-speed Train(KHST) have been analyzed to investigate the performance on the stability, the safety and the ride comfort. Multi-body dynamics analysis program using Recursive method, called RecurDyn, have been employed in the numerical simulation. To model the wheel-rail contact, the RecurDyn uses its built-in module which uses the square root creep law. The accuracy of the rail module in RecurDyn. however, decreases in the analysis of flange contact because it linearizes the shape of the wheel and rail. To solve this problem, a nonlinear contact theory have been developed that considers the profiles of the wheel and rail. The results show that the KHST still needs more stability. The problem should be solved by the examinations of module and modeling.

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Lightweight Design for Front Knuckle of Solar-Powered Vehicle using Topology Optimization (위상최적화를 이용한 태양광 자동차 프론트 너클의 경량화 설계)

  • Jeong, DaeYoung;Lee, JunYoung;Kim, MoonYoung;Yim, HongJae
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.594-597
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    • 2014
  • 본 논문에서는 국제 태양광 자동차 대회를 참가하는 태양광 자동차 프론트 너클의 경량화 설계에 관한 연구를 진행한다. 이를 위해 Cattle grid 를 포함한 실제 주행환경과 태양광 자동차를 동역학 시뮬레이션 모델로 구성하고 대회에서 차량의 평균속도인 70Km/h 로 주행 시, 서스펜션에서 발생되는 동하중을 측정하였다. 프론트 너클을 유한요소로 구성하고 다물체 동역학 시뮬레이션에서 도출된 하중들로 위상최적기법을 통해 프론트 너클의 경량화를 이루었다. 마지막으로 피로해석을 수행하여 그 타당성을 검증하였다.

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Simulation for Belt Transport System using Crowning Roller (Crowning 롤러를 이용한 벨트 이송 시스템의 시뮬레이션)

  • Lyu, Sang-Heon;Ihu, Yong-Seok;Choi, Yeon-Sun;Koo, J.C.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.676-679
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    • 2006
  • The media transport in automatic office machines such as printers, ATMs, copying machines is achieved by a complicated belt system. The system generally uses a crowning roller and belt which has been well-known for its intrinsic belt centering advantage during its operation. Since the modern office machines require precise high operating speed, stabilization of media transporting system has been one of the important issues of the machine design. Even a minor defect of the belt or the roller in the transport system directly affects its operating stability. This paper delivers a simulation technique that combines a multi-body dynamics analysis routine and a FEM based flexible continuum modeling for the efficient simulation of the flexible media transport problems.

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Simulation for Defect Diagnosis in Belt Transport System (벨트 이송 시스템의 결함 진단을 위한 시뮬레이션)

  • Lee, Nam-Hoon;Lyu, Sang-Heon;Ihn, Yong-Seok;Choi, Yeon-Sun;Koo, J.C.
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.16 no.4 s.109
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    • pp.366-371
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    • 2006
  • As functional requirements of automatic office machines like printers, Automatic Tellex Machines(ATMs), copying machines are on a trend for the higher speed and precision, extensive technical advances are being developed and implemented in the industry. Media transport system is a device to convey a sheet of paper in ATMs and printers. The stability of media transport system is a matter of concern as their operating throughput rapidly increases. And defects of belts or rollers in a transport system directly affect the level of stability of the system. Therefore an automatic diagnostic system for predicting various defects is necessary for the stable operation of the media transport system. A simulation based on multi-body dynamics has been done for a feasibility study of a system design for the defect anticipation.

Development of the direct boundary element method for thin bodies with general boundary conditions (일반 경계 조건을 가진 얇은 물체에 대한 직접 경계 요소법의 개발)

  • 이강덕;이덕주
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.04a
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    • pp.701-708
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    • 1997
  • A direct boundary element method(DBEM) is developed for thin bodies whose surfaces are rigid or compliant. Th eHelmholtz integral equation and its normal derivative integral equation are adopted simultaneously to calculate the pressure on both sides of the thin body, instead of the jump values across it, to account for the different surface conditions of each side. Unlike the usual assumption, the normal velocity is assumed to be discontinuous across the thin body. In this approach, only the neutral surface of the thin body has to be discontinuous across the thin body. In this approach, only the neural surface of the thin body has to be discretized. The method is validated by comparison with analytic and/or numerical results for acoustic scattering and radiation from several surface conditions of the thin body; the surfaces are rigid when stationary or vibrating, and part of the interior surface is lined with a sound-absorbing material.

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A Study on the Prediction of the Impact Harshness for a Passenger Vehicle (차량의 임팩트하쉬니스 성능 예측 연구)

  • Kim, Jin Hong;Jeong, Il Soo;Kim, Myung Gyu;Shim, Jeong Soo;Lee, Sang Woo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2012.10a
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    • pp.613-616
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    • 2012
  • A multi body simulation (MBS) model is developed for predicting the impact harshness of the vehicle. Impact harshness is the vehicle performance to evaluate the impulsive vibration behavior during driving over an obstacle of the road. Thus, the approach is simulated on the time domain for considering the transient behavior of the vehicle. The validity of vehicle component modeling of bushes, dampers and structure flexibilities is verified. The simulations are compared with the test results in both of vertical and longitudinal directions. In particular, the vertical vibration of the vehicle is significantly affected by the body flexibility. Through the sensitivity analysis, main factors for the impact harshness performance are investigated.

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Design and evaluations of Tonpilz Transducers with self noise suppressing structures (저소음 Tonpilz 트랜스듀서의 설계방안 연구)

  • 임종인
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1996.06a
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    • pp.1-3
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    • 1996
  • 수중 트랜스듀서는 진동하는 물체위에 설치되어 다양한 외부 소음원이 유입되는 환경에 노출되어 있다. 외부 소음원으로는 선체 진동. 프로펠러 소음, 그리고 유동 유기 소음들을 들 수 있고, 트랜스듀서의 실제 작동시 이들의 레벨이 상당히 높아서 센서의 정확한 작동에 장애가 되고 있다. 본 논문에서는 외부 소음원에 무관한 고 정밀, 저 소음 특성을 지닌 음향센서를 개발하기 위하여 유한요소법 (FEN)을 사용하여 소음 전달 특성을 분석하고, air pocket과 음향 감쇠층의 다양한 조합으로 이루어진 구조를 개선한 음향센서의 설계 및 내소음성 평가를 하였다. 또한 사용한 음향 감쇠층의 최적 물성을 제시하고자 한다. 그 결과 센서 측면 하단부에 소음원이 위치할 경우 가장 큰 잡음 신호로 작용하며, 구조를 변경한 결과 기존 음향센서에 비해 55% 이상 내 소음성을 증진 시켰다. 그리고 음향 감쇠층의 최적 음향 임피던슨는 1 Mrayl 이하 혹은 4mrayl 이상으로 분석되었다.

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Structure Borne Noise Analysis of a Flexible Body in Multibody System (다물체계내 유연체의 구조기인 소음해석)

  • 김효식
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2003.05a
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    • pp.130-135
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    • 2003
  • This paper presents the method for structure borne noise analysis of a flexible body in multibody system. The proposed method is the superposition method using flexible muitibody dynamic analysis and finite element one. This method is executed in 3 steps. In the la step, time dependent quantities such as dynamic loads, modal coordinates ana gross body motion of the flexible body are calculated efficiently through flexible multibody dynamic analysis. And frequency response functions are computed using Fourier transforms of those time dependent quantities. In the 2\^nd/ step, acoustic pressure coefficients are obtained through structure-acoustic coupling analysis by finite element analysis. In the final step, frequency responses of acoustic pressure at the acoustic nodes are recovered through linear superposition of frequency response functions with acoustic pressure coefficients. The accuracy of the proposed method is verified in the numerical example of a simple car model.

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Hypersonic flow calculations using AUSMPW+ and Shock-Aligned Grid Technique (AUSMPW+ 수치기법과 충격파 정렬 격자 기법을 이용한 극초음속 유동장 해석)

  • Kim K. H.;Kim C.;Rho O. H.
    • 한국전산유체공학회:학술대회논문집
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    • 1999.05a
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    • pp.73-78
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    • 1999
  • 극초음속 유동장의 정확한 해석을 위해 AUSMPW+ 수치기법과 충격파 포착시 생기는 수치오차를 제거하기 위해 충격파 정렬 기법(Shock-Aligned Grid Technique)을 개발하였다. AUSMPW+ 수치기법은 자체 수치점성이 적은 수치기법으로 점성 경계층 계산시 정확한 계산결과를 보여주며 기존의 AUSM 계열이 가지는 문제점인 물성치의 진동 현상을 제거한 수치기법이다. 원통형과 무딘 물체 주위의 극초음속 유동장 해석을 통해 공력이 진동현상 없이 정확하게 계산됨을 확인하였다. 그리고 충격파 정렬 기법의 특성을 파악하기 위해 충격파 반사문제와 충격파-충격파 상호작용 문제를 해석하여 수치오차 없이 충격파를 포착할 수 있음을 보였다. 또한 화학적 평형 비평형 유동 영역까지 충격파 정렬 격자 기법을 확장하였다.

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A New Method for Extracting Resonance Information in Acoustic Wave Resonance Scattering (음향파 공명 산란의 새로운 해석방법)

  • 이희남;박영진
    • Journal of KSNVE
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    • v.9 no.2
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    • pp.409-417
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    • 1999
  • A new method is proposed for the isolation of resonances from scattered waves for the isolaton of resonances from scattered waves for acoustic wave resonance scattering problems. The resonance scattering function consisting purely of resonance information is defined. Acoustic wave scattering from a variety of submerged bodies is numerically analyzed. The classical resonance scattering theory (RST) and the new method compute identical magnitudes of the resonances from each partial wave, however, the phases are significantly different. The exact π-radians phase shifts through the resonance and anti-resonance frequencies show that the proposed method properly extracts the vibrational resonance information of the scatterer. Due to the differences in phases of the resonances from each partial wave, the new method and RST generate different total resonance spectra.

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