• 제목/요약/키워드: Nonlinear Modeling

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퍼지 시스템을 이용한 비선형 질소제거 SBR 공정의 모델링 (Modeling of Nonlinear SBR Process for Nitrogen Removal Using Fuzzy Systems)

  • 김동원;박장현;이호식;박영환;박귀태
    • 한국지능시스템학회논문지
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    • 제14권2호
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    • pp.190-194
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    • 2004
  • 본 논문에서는 비선형 생화학적인 공정의 모델링을 위해 퍼지시스템이 응용된 것을 보인다. SBR 반응조에서 질소제거를 위한 수처리 공정이 제시되었으며, 이 공정의 ORP값을 모델링하고 동정하기 위해 서로 다른 후반부 다항식을 가진 퍼지시스템이 소개되었다. 퍼지모델링 결과를 비교하고 분석하며 또한 제안된 방법에 의해 비선형 공정이 합리적이고 효율적으로 모델링 될 수 있음을 본 논문에서 보인다.

Sub-modeling을 이용한 end-to-end 문합의 비선형 해석 (Nonlinear Analysis of End-to-End Anastomosis Using Sub-modeling)

  • 한근조;안성찬;심재준
    • 한국정밀공학회지
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    • 제20권2호
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    • pp.192-198
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    • 2003
  • A finite element analysis of end-to-end artery/PTFE anastomosis has been presented in this study to evaluate the distribution of compliance and stresses in the vicinity of the anastomosis due to any mismatch in compliance characteristics. The artery wall was assumed to be made of linear isotropic material in this simplified model and a nonlinear analysis and convergency study with respect to increasing meshed element numbers were performed with a mean artery pressure loading of the artery-PTFE model. Also, sub-modeling method was Introduced to progress the accuracy of the finite element analysis. The results are as follow : 1. A hypercompliant zone on the artery side was observed around 4.Omm from the anastomosis and a high hoop stresses in the wall of artery and PTFE was dominant. 2. An artery displays large deformation so that nonlinear analysis and sub-modeling method was used. 3. An anastomosis with the thinner thickness and larger diameter PTFE (B type) could reduce the compliance disagreement.

축방향 왕복운동을 하는 집중질량을 가진 외팔보의 비선형 동적 모델링 및 안정성 해석 (Nonlinear Dynamic Modeling and Stability Analysis of an Axially Oscillating Cantilever Beam With a Concentrated Mass)

  • 홍정환;유홍희
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2003년도 춘계학술대회논문집
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    • pp.477-482
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    • 2003
  • A nonlinear modeling method for an axially oscillating cantilever beam with a concentrated mass is presented in this paper. Hybrid deformation variables are employed fur the modeling method with which frequency response characteristics of axially oscillating cantilever beams are investigated. The geometric nonlinear effects of stretching and curvature are considered to accurately predict the frequency response characteristics of the oscillating cantilever beam. The effects of the magnitude and the location on the concentrated mass on the frequency characteristics are investigated. It is found that the dynamic instability is significantly influenced by the two parameters.

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STT 미사일의 모델링 오차 보상을 위한 적응 제어 (Adaptive control to compensate the modeling error of STT missile)

  • 최진영;좌동경
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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    • pp.1292-1295
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    • 1996
  • This paper proposes an adaptive control technique for the autopilot design of STT missile. Dynamics of the missile is highly nonlinear and the equilibrium point is vulnerable to change due to fast maneuvering. Therefore nonlinear control techniques are desirable for the autopilot design of the missile. The nonlinear controller requires the exact model to obtain satisfactory performance. Generally a look-up table is used for the dynamic coefficients of a missile, so there must be coefficients error during actual flight, and the performance of the nonlinear controller using these data can be degraded. The proposed adaptive control technique compensates the nonlinear controller with modeling error resulting from the error of aerodynamic data and disturbance. To investigate the usefulness, the proposed method is applied to autopilot design of STT missile through simulations.

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7자유도 센서차량모델 제어를 위한 비선형신경망 (Nonlinear Neural Networks for Vehicle Modeling Control Algorithm based on 7-Depth Sensor Measurements)

  • 김종만;김원섭;신동용
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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    • pp.525-526
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    • 2008
  • For measuring nonlinear Vehicle Modeling based on 7-Depth Sensor, the neural networks are proposed m adaptive and in realtime. The structure of it is similar to recurrent neural networks; a delayed output as the input and a delayed error between the output of plant and neural networks as a bias input. In addition, we compute the desired value of hidden layer by an optimal method instead of transfering desired values by backpropagation and each weights are updated by RLS(Recursive Least Square). Consequently, this neural networks are not sensitive to initial weights and a learning rate, and have a faster convergence rate than conventional neural networks. This new neural networks is Error Estimated Neural Networks. We can estimate nonlinear models in realtime by the proposed networks and control nonlinear models.

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Modeling nonlinear behavior of gusset plates in the truss based steel bridges

  • Deliktas, Babur;Mizamkhan, Akhaan
    • Structural Engineering and Mechanics
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    • 제51권5호
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    • pp.809-821
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    • 2014
  • The truss based steel bridge structures usually consists of gusset plates which lose their load carrying capacity and rigidity under the effect of repeated and dynamics loads. This paper is focused on modeling the nonlinear material behavior of the gusset plates of the Truss Based Bridges subjected to dynamics loads. The nonlinear behavior of material is characterized by a damage coupled elsto-plastic material models. A truss bridge finite element model is established in Abaqus with the details of the gusset plates and their connections. The nonlinear finite element analyses are performed to calculate stress and strain states in the gusset plates under different loading conditions. The study indicates that damage initiation occurred in the plastic deformation localized region of the gusset plates where all, diagonal, horizontal and vertical, truss member met and are critical for shear type of failure due tension and compression interaction. These findings are agreed with the analytical and experimental results obtained for the stress distribution of this kind gusset plate.

비선형 시스템의 신경회로망을 이용한 모델링 기법 (Nonlinear System Modeling Using a Neural Networks)

  • 정길도;노태수;홍동표
    • 한국정밀공학회지
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    • 제13권12호
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    • pp.22-29
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    • 1996
  • In this paper the nodes of the multilayer hidden layers have been modified for modeling the nonlinear systems. The structure of nodes in the hidden layers is built with the feedforward, the cross talk and the recurrent connections. The feedforward links are mapping the nonlinear function and the cross talks and the recurent links memorize the dynamics of the system. The cross talks are connected between the modes in the same hidden layers and the recurrent connection has self feedback, and these two connections receive one time delayed input signals. The simplified steam boiler and the analytic multi input multi output nonlinear system which contains process noise have been modeled using this neural networks.

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판 스프링의 비선형 동특성 해석 (Finite Element Modeling and Analysis of Nonlinear Dynamic characterisics of Leaf spring)

  • 임홍재;권영일
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 1996년도 춘계학술대회 논문집
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    • pp.842-846
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    • 1996
  • Leaf springs are widely used as a major suspension component in many commercial vehicles, such as buses, trucks, etc. They have a complex dynamic behavior due to the geometric nonlinear and the contact mechanism between the leaves. The interface conditions between the leaves play a significant role in the global behavior of the comfort and ride of the vehicle system. The paper concentrates on modeling leaf springs and contact frictions between the leaves using a nonlinear finite element approach. A nonlinear load-displacement hysteresis curve for the leaf spring is simulated and its results are compared with test results.

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Virtual Modeling Data와 비선형 해석 프로그램의 Interface 설계 (Interface Design of Virtual Modeling Dataand Nonlinear Analysis Program)

  • 박재근;이헌민;조성훈;이광명;신현목
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2008년도 정기 학술대회
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    • pp.100-103
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    • 2008
  • Recently Development of construction system that subjective operators share and control information efficiently based on the three-dimensional space and design information throughout life cycle of construction project is progressing dynamically. In case of civil structures which are infrastructure, Demand for structure of complex system which has multi-functions such as super and smart bridges and express rails is increasing and system development which computerizes and integrates process of structure design is in need. For that, research about link way between three dimensional modeling data and structure analysis programs should be preceded. In this research, therefore, research about interface design between three dimensional virtual modeling data to automate efficient civil-structure-design and nonlinear finite element analysis program which is made up of reinforced concrete material model that express material's character clearly.

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축방향 왕복운동을 하는 외팔보의 복합변형변수를 이용한 비선형 모델링 및 주파수 응답특성 (Nonlinear Modeling Employing Hybrid Deformation Variables and Frequency Response Characteristics of a Cantilever Beam Undergoing Axially Oscillating Motion)

  • Kim, Na-Eun;Hyun, Sang-Hak;Yoo, Hong-Hee
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 추계학술대회논문초록집
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    • pp.331.2-331
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    • 2002
  • A modeling method for cantilever beams undergoing axially oscillating motion is presented in this paper. Hybrid deformation variables are employed for the modeling method. Frequency response characteristics are investigated with the modeling method. It is shown that the geometric nonlinear effects of stretching and curvature play important roles to accurately predict the dynamic response. (omitted)

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