• 제목/요약/키워드: Dynamic numerical analysis

검색결과 2,585건 처리시간 0.03초

접촉면에서 모든 적합조건을 만족시키는 동적인 접촉현상의 해법 (Dynamic Contact Analysis Satisfying All the Compatibility Conditions on the Contact Surface)

  • 이기수
    • 대한기계학회논문집
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    • 제19권5호
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    • pp.1243-1250
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    • 1995
  • For the numerical solution of frictional dynamic contact problems, correct contact points and displacements are determined by iteratively reducing the displacement error vector monotonically toward zero And spurious oscillations are prevented from the solution by enforcing the velocity and acceleration compatibilities of the contact points with the corresponding error vectors. Numerical simulations are conducted to demonstrate the accuracy of the solution and the necessity of the velocity and acceleration compatibilities on the contact surface.

Dynamic interaction analysis of actively controlled maglev vehicles and guideway girders considering nonlinear electromagnetic forces

  • Min, Dong-Ju;Lee, Jun-Seok;Kim, Moon-Young
    • Coupled systems mechanics
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    • 제1권1호
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    • pp.39-57
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    • 2012
  • This study intends to explore dynamic interaction behaviors between actively controlled maglev vehicle and guideway girders by considering the nonlinear forms of electromagnetic force and current exactly. For this, governing equations for the maglev vehicle with ten degrees of freedom are derived by considering the nonlinear equation of electromagnetic force, surface irregularity, and the deflection of the guideway girder. Next, equations of motion of the guideway girder, based on the mode superposition method, are obtained by applying the UTM-01 control algorithm for electromagnetic suspension to make the maglev vehicle system stable. Finally, the numerical studies under various conditions are carried out to investigate the dynamic characteristics of the maglev system based on consideration of the linear and nonlinear electromagnetic forces. From numerical simulation, it is observed that the dynamic responses between nonlinear and linear analysis make little difference in the stable region. But unstable responses in nonlinear analysis under poor conditions can sometimes be obtained because the nominal air-gap is too small to control the maglev vehicle stably. However, it is demonstrated that this unstable phenomenon can be removed by making the nominal air-gap related to electromagnetic force larger. Consequently it is judged that the nonlinear analysis method considering the nonlinear equations of electromagnetic force and current can provide more realistic solutions than the linear analysis.

트랙좌표계를 이용한 철도차량의 동역학 해석에 관한 연구 (A Study on the Dynamic Analysis of Railway Vehicle by Using Track Coordinate System)

  • 강주석
    • 한국자동차공학회논문집
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    • 제21권2호
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    • pp.122-130
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    • 2013
  • Rail geometries such as cant, grade and curvature can be easily represented by means of a track coordinate system. In this analysis, in order to derive a dynamic and constraint equation of a wheelset, the track coordinate system is used as an intermediate stage. Dynamic and constraint equations of railway vehicle bodies except the wheelset are written in the Cartesian coordinate system as a conventional method. Therefore, whole dynamic equations of a railway vehicle are derived by combining wheelset dynamic equations and dynamic equations of railway vehicle bodies. Constraint equations and constraint Jacobians are newly derived for the track coordinate system. A process for numerical analysis is suggested for the derived dynamic and constraint equations of a railway vehicle. The proposed dynamic analysis of a railway vehicle is validated by comparison against results obtained from VI-RAIL analysis.

Dynamic Analysis of Sliders in Optical Memory System

  • Gyeong Hwa, Im;Chae Heon, An
    • 한국반도체및디스플레이장비학회:학술대회논문집
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    • 한국반도체및디스플레이장비학회 2003년도 추계학술대회 발표 논문집
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    • pp.200-206
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    • 2003
  • Identification method is formulated to evaluate the dynamic characteristics of air bearings under NFR (Near Field Recording) sliders. Using dynamic analysis, impulse responses and frequency response functions of NFR sliders are obtained on numerical non-linear models including rigid motion of slider and fluid motion of air bearing under the slider. System parameters are identified by modal analysis method and instrumental variable method. The identified system parameters of sliders are utilized to evaluate the dynamic characteristics of air bearings.

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이동물체에 의한 보 구조물의 진동 해석 (Vibration Analysis of the Beam Structure with a Moving Mass)

  • 이우식;임강민
    • 전산구조공학
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    • 제8권4호
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    • pp.57-64
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    • 1995
  • 본 논문에서는 이동물체에 의해 가진 받는 보의 동적반응을 보다 용이하게 다룰 수 있는 간결한 수치해석 알고리즘을 제안하였다. 구조물과 이동물체를 각각 균일한 Euler보와 질점으로 모델링하여 보의 운동방정식을 유도하였으며 이 식을 유연영향함수를 이용하여 적분형 미분방정식으로 바꾸어줌으로써 수치해석에 적용할 수 있는 형태로 바꾸어 주었다. 유도된 운동방정식을 모우드 해석기법을 이용하여 수치해를 구하였으며 기존의 수치해석 연구결과들과 비교하여 본 연구결과의 타당성을 검증함으로써 본 연구에서 개발한 수치해석 알고리즘은 이동물체에 의해 가진받는 보의 초기 해석과 설계과정에서 효율적으로 사용할 수 있음을 보였다.

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Mesoscale modelling of concrete for static and dynamic response analysis -Part 1: model development and implementation

  • Tu, Zhenguo;Lu, Yong
    • Structural Engineering and Mechanics
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    • 제37권2호
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    • pp.197-213
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    • 2011
  • Concrete is a heterogeneous material exhibiting quasi-brittle behaviour. While homogenization of concrete is commonly accepted in general engineering applications, a detailed description of the material heterogeneity using a mesoscale model becomes desirable and even necessary for problems where drastic spatial and time variation of the stress and strain is involved, for example in the analysis of local damages under impact, shock or blast load. A mesoscale model can also assist in an investigation into the underlying mechanisms affecting the bulk material behaviour under various stress conditions. Extending from existing mesoscale model studies, where use is often made of specialized codes with limited capability in the material description and numerical solutions, this paper presents a mesoscale computational model developed under a general-purpose finite element environment. The aim is to facilitate the utilization of sophisticated material descriptions (e.g., pressure and rate dependency) and advanced numerical solvers to suit a broad range of applications, including high impulsive dynamic analysis. The whole procedure encompasses a module for the generation of concrete mesoscale structure; a process for the generation of the FE mesh, considering two alternative schemes for the interface transition zone (ITZ); and the nonlinear analysis of the mesoscale FE model with an explicit time integration approach. The development of the model and various associated computational considerations are discussed in this paper (Part 1). Further numerical studies using the mesoscale model for both quasi-static and dynamic loadings will be presented in the companion paper (Part 2).

Dynamic analysis of a laminated composite beam under harmonic load

  • Akbas, S.D.
    • Coupled systems mechanics
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    • 제9권6호
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    • pp.563-573
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    • 2020
  • Dynamic responses of a laminated composite cantilever beam under a harmonic are investigated in this study. The governing equations of problem are derived by using the Lagrange procedure. The Timoshenko beam theory is considered and the Ritz method is implemented in the solution of the problem. The algebraic polynomials are used with the trivial functions for the Ritz method. In the solution of dynamic problem, the Newmark average acceleration method is used in the time history. In the numerical examples, the effects of load parameter, the fiber orientation angles and stacking sequence of laminas on the dynamic responses of the laminated beam are investigated.

Dynamic Model to Predict Effect of Race Waviness on Vibrations Associated with Deep-Groove Ball Bearing

  • Hwang, Pyung;Nguyen, Van Trang
    • Tribology and Lubricants
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    • 제30권1호
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    • pp.64-70
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    • 2014
  • This paper presents a numerical model for investigating the structural dynamics response of a rigid rotor supported on deep-groove ball bearings. The numerical model was used to investigate the influence of race waviness on the dynamic characteristics of a rotor ball bearing system, which is very important from a design viewpoint. The forth-order Runge-Kutta numerical integration technique was applied to determine the time displacement response, Poincare map, and frequency spectra. The analysis demonstrated that the model can be used as a tool for predicting the nonlinear dynamic behavior of a rotor ball bearing system under different operating conditions. The results of this study may help further understanding of the nonlinear dynamics of a rotor bearing system.

경기장 구조물의 효율적인 진동해석 (Efficient Vibration Analysis of Stadium Structure)

  • 김기철;이동근
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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    • pp.475-482
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    • 2001
  • Stadium stand could be led to significant dynamic response due to rhythmical activities of spectator. The dynamic loads induced by spectators movements are considered as static loads in design standard of many countries but these loads have dynamic characteristics. So, it is desirable to apply measured dynamic loads created by spectator activities and to analyze the dynamic behavior of stadium system. The precise investigation of the dynamic loads on stadium structures and the accurate analysis of dynamic behavior of stadium systems are demanded for effective design. As the floor mesh of stadium stand is refined, the number of nodes increase in numerical analysis. So it is difficult to analyze entire stadium structures and much more computer memory are necessary for vibration analysis of stadium system. In this study, the various dynamic loads induced by spectator movements are measured and analyzed. And new modeling method that reduce the nodal points of stadium systems are introduced. Vibration analysis of stadium system is executed to inspect the accuracy and the efficiency of proposed method in this paper.

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붐(Boom)의 탄성을 고려한 해상크레인의 비선형 정적/동적 거동을 위한 수치 해석 (Numerical Analysis for Nonlinear Static and Dynamic Responses of Floating Crane with Elastic Boom)

  • 차주환;박광필;이규열
    • 대한기계학회논문집A
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    • 제34권4호
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    • pp.501-509
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    • 2010
  • 해상크레인은 크레인을 탑재한 선박으로서, 조선소에서 대형 블록이나 구조물의 탑재 및 해상 운송 작업에 사용된다. 본 논문에서는 해상크레인과 중량물의 전후 동요(Surge), 상하 동요(Heave), 종 동요(Pitch)에 대한 정적/동적거동을 분석하였다. 이 때, 유연 다물체계 동역학을 적용하여 해상크레인의 붐(boom)을 탄성으로 고려하였으며, 플로팅 프레임(floating frame)과 노드 좌표(nodal coordinates)를 사용하였다. 질량 행렬, 탄성 강성 행렬, 2 차 속도 벡터, 일반화 좌표 방향으로 작용하는 외력 등을 고려하여 모든 운동이 연성된 비선형 운동 방정식을 구성하였다. 외력으로는 비선형 유체정역학 힘, 선형화된 유체동역학 힘, wire rope 힘, 계류력이 고려되었다. 수치 해석을 위해 Hilber-Hughes-Taylor 방법을 비선형 운동방정식에 적용하였다. 정적 거동 분석을 통한 정적 평형 자세를 고려한 경우와 고려하지 않은 경우에 대해 결과를 비교하였으며, 수치 해석 방법에 대한 정적/동적 거동 분석 결과를 비교하였다.