• Title/Summary/Keyword: Nonlinear Modelling

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Lessons from the analysis of a 3-D concrete shear wall

  • Vecchio, F.J.
    • Structural Engineering and Mechanics
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    • v.6 no.4
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    • pp.439-455
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    • 1998
  • A three-dimensional static nonlinear finite element analysis was performed on the NUPEC large-scale flanged shear wall, which was the subject of an international study program. Details of the constitutive models and analysis procedures used are provided, and the results of the analysis are presented and discussed. The analytical results are compared to the experimentally observed behaviour, and reasonable correlation is observed. Deficiencies in the modelling are identified. In addition, a parametric study is undertaken to investigate factors and mechanisms influencing both the observed behaviour and the calculated response. Finally, a cyclic load analysis of the wall is described and discussed. The paper serves to point out aspects in modelling that are critical to both producing realistic results, and correctly interpreting those results.

Intelligent computer modelling and simulation for the large amplitude of nano systems

  • Yi, Wenjuan
    • Advances in nano research
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    • v.13 no.1
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    • pp.63-75
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    • 2022
  • The nonlinear dynamic behavior of a nonuniform small-scale nonlocal beam is investigated in this work. The nanobeam is theoretically modeled using the nonlocal Eringen theory, as well as a few of Von-nonlinear Kármán's theories and the classical beam theory. The Hamilton principle extracts partial differential equations (PDE) of an axially functionally graded (AFG) nano-scale beam consisting of SUS304 and Si3N4 throughout its length, and an elastic Winkler-Pasternak substrate supports the tapered AFG nanobeam. The beam thickness is a function of beam length, and it constantly varies throughout the length of the beam. The numerical solution strategy employs an iteration methodology connected with the generalized differential quadratic method (GDQM) to calculate the nonlinear outcomes. The nonlinear numerical results are presented in detail to examine the impact of various parameters such as nonlinear amplitude, nonlocal parameter, the component of the elastic foundation, rate of cross-section change, and volume fraction parameter on the linear and nonlinear free vibration characteristics of AFG nanobeam.

Implementation of Bilateral Control of fuzzy Robot Hand using Analytic Hierachy Process (계층적 분석방법을 이용한 퍼지 로봇 핸드의 양방향 제어의 구현)

  • 진현수
    • Proceedings of the IEEK Conference
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    • 2003.07c
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    • pp.2827-2830
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    • 2003
  • Tele manipulator is distingushed from industrial robot by iterating same specified work. Manipulator operator is included in control loop for controlling the telemanipulator because he decide directly during the work and order controllabily reducing the modelling error of telemanipulator which depend on the PID controller. But position-force control method of bidirectional control impose unsafety of vibiration and Analytic Hierachy Method can stabilize for reducing nonlinear modelling error by expert operator because of transformation empirical control rule to linear model.

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Some Sufficient Conditions for Output Regulation of Uncertain Nonlinear Systems (불확실 비선형 시스템의 출력제어를 위한 충분조건)

  • 하인중;최종호;고명삼
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.25 no.2
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    • pp.162-167
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    • 1988
  • In this note, we present some sufficient conditions on the structure of modelling uncertainties for output regualtion of uncertain systems. It turns out that these conditions include as special cases the ordinary matching conditions for stage regulation of uncertain systems and the disturbance decoupling condition. the previous restrictions on the structure of modelling uncertainties can be considerably relaxed in the case of output regulation. The significance of out result is illuminated through a simple example.

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Performance of structural-concrete members under sequential loading and exhibiting points of inflection

  • Jelic, I.;Pavlovic, M.N.;Kotsovos, M.D.
    • Computers and Concrete
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    • v.1 no.1
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    • pp.99-113
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    • 2004
  • The article reports data on, and numerical modelling of, beams exhibiting points of inflection and subjected to sequential loading. Both tests and analysis point to inadequacies in current codes of practice. An alternative design methodology, which is strongly associated with the notion that contraflexure points should be designed as "internal supports", is shown to produce superior performance even though it requires significantly less secondary reinforcement than that advocated by codes.

Nonlinear simulation of tunnel linings with a simplified numerical modelling

  • Zhao, Huiling;Liu, Xian;Bao, Yihai;Yuan, Yong
    • Structural Engineering and Mechanics
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    • v.61 no.5
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    • pp.593-603
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    • 2017
  • A high-efficiency simplified modelling approach is proposed for investigating the nonlinear responses of reinforced concrete linings of shield tunnels. Material and geometric nonlinearities are considered in the analysis of the lining structures undergoing large deformation before ultimately losing the load-carrying capacity. A beam-spring element model is developed to capture the force-transfer mechanism between lining segments and radial joints. The developed model is validated by comparing analyzed results to experimental results of a single-ring lining structure under two loading conditions: the ground overloading and the lateral unloading respectively. The results show that the lining structure under the lateral unloading due to excavation on the both sides of the tunnel is more vulnerable compared to the case of ground overloading on the top of the tunnel. A parameter study is conducted and results indicate that the lateral pressure coefficient has the greatest influence on the behaviour of the lining structure.

Analysis of RP Power Amplifier Nonlinearity and BER Characteristics for Multi­Carrier Transmission System (다중반송 전송시스템을 위한 RF 전력증폭기의 비선형 특성과 BER관계 분석)

  • 신동환;이영철
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.7 no.8
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    • pp.1612-1620
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    • 2003
  • This papers describes a nonlinear transfer function modelling of designed GaAs FET power amplifier by measured and simulated values of designed PA amplifier for multi­carrier transmission system, With the results of PA nonlinearity characteristic, we can estimates AM­AM and AM­PM of designed PA. According to the estimated nonlinear characteristics, we can analysis the ACPR of PA for spectral regrowth, the error vector measurement(EVM) of constallation signals and bit error rate of QPSK and 64­QAM. The suggested nonlinear modelling results are used to get an accurate estimate of digital characteristics between PA amplifier and wireless multi­carrier transmission system using OFDM.

Development of an Educational System and Real Time Nonlinear Control (I) (교육용 시스템 개발과 실시간 비선형 제어(I))

  • 박성욱
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.51 no.12
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    • pp.562-570
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    • 2002
  • The Purpose of this paper is to design and manufacture an educational system in order to demonstrate the causes and effects of electromagnetic induction.'rho educational system described in this study is a "jumping ring apparatus". This system demonstrates the principle of electromagnetic induction, a force from AC sources, Lenz's law of repulsion and transformer. The educational system is composed of a jumping ring apparatus, a sensor array, encoder, A/D converter, D/A converter and nonlinear controller. The educational system is controlled by 586 PC using Turbo C program. The sensor array is composed of 20 optical sensors. The nonlinear controller consists of nonlinear control algorithm and control board included SCR, FET and phase controller. The A/D converter is used to show the height of ring position to analog for an education purpose. The control signal calculated from the nonlinear control of algorithm send control board through 8 bit D/A convertor. Experiment results are given to verify that Proposed nonlinear controller is useful in on line control of the educational system.al system.

Nonlinear ANC using a NPVSS-NLMS algorithm and online modelling of an acoustic linear feedback path (NPVSS-NLMS 알.고리즘과 온라인 선형 피드백 경로 모델링을 이용한 비선형 능동 소음 제어)

  • Seo, Jae-Beom;Nam, Sang-Won
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.59 no.5
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    • pp.1001-1004
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    • 2010
  • Acoustic feedback and background noise variation can degrade the performance of an active noise control (ANC) system. In this paper, nonlinear ANC using a non-parametric VSS-NLMS (or NPVSS-NLMS) algorithm and online feedback path modeling is proposed, whereby the conventional linear ANC with online acoustic feedback-path modeling is further extended to nonlinear Volterra ANC with a linear acoustic feedback path. In particular, the step-size of the NPVSS-NLMS algorithm is controlled to reduce the effect of background noise variation in the ANC system. Simulation results demonstrate that the proposed approach yields better nonlinear ANC performance compared with the conventional nonlinear ANC method.