• 제목/요약/키워드: Nonlinear Design

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P-$\Delta$ 효과를 고려한 철골 구조물의 비선형 동적거동 평가 (Evaluation of Nonlinear Dynamic Behavior for Steel Moment Frame Structures Considering P-$\Delta$ Effects)

  • 최원호;이주완;이동근
    • 한국지진공학회:학술대회논문집
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    • 한국지진공학회 2001년도 추계 학술발표회 논문집 Proceedings of EESK Conference-Fall 2001
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    • pp.235-242
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    • 2001
  • Inelastic seismic response of steel moment frame structures, which are usually quite gravity load and subject to large displacement under severe earthquake, may be severly influenced by the structure P-Δ effects. The P-Δ effect may have an important impact on the dynamic behavior of the structure in the nonlinear seismic analysis. In multi degree of freedom systems P-Δ effects may significantly affect only a subset of stories or a single story alone. Therefore, a story drift amplification of structure is happened by P-Δeffects and such nonlinear dynamic behaviors are very difficult to evaluate in the structures. In this study, two systems having different design methods of steel moment frame structures are investigated to evaluate the P-Δ effects due to gravity load. The plastic hinge formations, maximum rotational ductility demands, and energy distribution will be compared and evaluated following whether the P-Δ effects are considered or not. And design methods are proposed for the prevention of the instability of structures which due to the P-Δ effects.

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Robust Stabilization of Decentralized Dynamic Surface Control for a Class of Interconnected Nonlinear Systems

  • Song, Bong-Sob
    • International Journal of Control, Automation, and Systems
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    • 제5권2호
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    • pp.138-146
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    • 2007
  • The analysis and design method for achieving robust stabilization of Decentralized Dynamic Surface Control (DDSC) is presented for a class of interconnected nonlinear systems. While a centralized design approach of DSC was developed in [1], the decentralized approach to deal with large-scale interconnected systems is proposed under the assumption that interconnected functions among subsystems are unknown but bounded. To provide a closed-loop form with provable stability properties, augmented error dynamics for N nonlinear subsystems with DDSC are derived. Then, the reachable set for errors of the closed-loop systems will be approximated numerically in the form of an ellipsoid in the framework of convex optimization. Finally, a numerical algorithm to calculate the $L_2$ gain of the augmented error dynamics is presented.

Topology optimization of nonlinear single layer domes by a new metaheuristic

  • Gholizadeh, Saeed;Barati, Hamed
    • Steel and Composite Structures
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    • 제16권6호
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    • pp.681-701
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    • 2014
  • The main aim of this study is to propose an efficient meta-heuristic algorithm for topology optimization of geometrically nonlinear single layer domes by serially integration of computational advantages of firefly algorithm (FA) and particle swarm optimization (PSO). During the optimization process, the optimum number of rings, the optimum height of crown and tubular section of the member groups are determined considering geometric nonlinear behaviour of the domes. In the proposed algorithm, termed as FA-PSO, in the first stage an optimization process is accomplished using FA to explore the design space then, in the second stage, a local search is performed using PSO around the best solution found by FA. The optimum designs obtained by the proposed algorithm are compared with those reported in the literature and it is demonstrated that the FA-PSO converges to better solutions spending less computational cost emphasizing on the efficiency of the proposed algorithm.

Planar Optical Waveguide Temperature Sensor Based on Etched Bragg Gratings Considering Nonlinear Thermo-optic Effect

  • Ahn, Kook-Chan;Lee, Sang-Mae;Jim S. Sirkis
    • Journal of Mechanical Science and Technology
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    • 제15권3호
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    • pp.309-319
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    • 2001
  • This paper demonstrates the development of optical temperature sensor based on the etched silica-based planar waveguide Bragg grating. Topics include design and fabrication of the etched planar waveguide Bragg grating optical temperature sensor. The typical bandwidth and reflectivity of the surface etched grating has been ∼0.2nm and ∼9%, respectively, at a wavelength of ∼1552nm. The temperature-induced wavelength change is found to be slightly non-linear over ∼200$^{\circ}C$ temperature range. Typically, the temperature-induced fractional Bragg wavelength shift measured in this experiment is 0.0132nm/$^{\circ}C$ with linear curve fit. Theoretical models with nonlinear temperature effect for the grating response based on waveguide and plate deformation theories agree with experiments to within acceptable tolerance.

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단층 래티스 돔의 기하학적 비선형 좌굴하중 추정에 관한 연구 (A Study on the Presumption of Geometrically Nonlinear Buckling Load of the Single Layer Latticed Dome)

  • 이정현;이상주;이진섭;최일섭;한상을
    • 한국공간구조학회:학술대회논문집
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    • 한국공간구조학회 2005년도 춘계학술발표회 및 정기총회 2권1호(통권2호)
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    • pp.147-153
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    • 2005
  • The single layer latticed dome is very sensitive on the slenderness ratio and half open angle of the elements, load condition, and the connection type because it is originazed by a lot of thin elements, so we have to use the geometrically nonlinear buckling load when the buckling of the structures is analyzed. But, it is very difficult to design the single layer latticed domes considered all conditions. Therefore the purpose of this paper is to propose the appropriate design method of the single layer latticed dome considered the geometrically nonlinear buckling load in base of the linear buckling load by the eigenvalue analysis.

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Robust High Gain Adaptive Output Feedback Tracking Control for Nonlinear Systems

  • Kohara, Koshiro;Mizumoto, Ikuro;Iwai, Zenta;Michino, Ryuji;Kumon, Makoto
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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    • pp.444-444
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    • 2000
  • For a class of nonlinear systems which satisfy a certain condition so called output feedback exponential passivity (OFEP), it is well known that one can easily design a high-gain output feedback control system. The designed high-gain controller has simple structure and high robustness. However, from the viewpoint of practical application, it is important to consider a robust control scheme for controlled systems for which some of the assumptions of output feedback stabilization are not valid. In this paper. we deal with a design problem of the robust high-gain adaptive output feedback control for the above-mentioned class of nonlinear systems with uncertain nonlinearities and/or disturbances.

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롤 운동을 고려한 차량의 정상상태 선회주행에 관한 연구 (A Study on the Steady-State Cornering of a Vehicle Considering Roll Motion)

  • 이장무;윤중락;강주석;배상우;탁태오
    • 한국자동차공학회논문집
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    • 제5권6호
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    • pp.89-102
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    • 1997
  • In this study, the steady state cornering behavior of a vehicle is investigated by using a numerical model that has parameters associated with roll motion. The nonlinear characteristics of tire cornering forces and aligning torques are presented in analytical forms using the magic formula. The sets of nonlinear algebraic equations that govern the cornering motion are solved by the Newton-Raphson iteration method. The vehicle design parameters are measured by SPMD(Suspension Parameter Measuring Device), and its results are verified by carrying out a skid pad test. The design parameters that are most affecting the steady state cornering behavior are classified into four factors, and the contributions of the factors to understeer gradient are then calculated.

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관류형 보일러의 비선형 저자모델 개발에 관한 연구 (A Study on Development of Nonlinear Low Order Models for an Once-through Type Boiler)

  • 이재용;채석;변증남;윤명중
    • 대한전기학회논문지
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    • 제36권1호
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    • pp.58-67
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    • 1987
  • By use of the real recorded data obtained from a power plant, nonlinear low-order state space models are developed for an once-through type power plant boiler. In order to understand the boiler dynamics and to use for the back-up controller design, the unknown model parameters have been estimated using the nonlinear estimation technique, i.e. Extended Kalman Filter method. It is shown that the simulation results coincide with the measurement data within 5% relative error range, which are acceptable from a back-up controller design point of view.

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Piecewise Regression Model for Solenoid Embedded Inductors Based on the Quasi-newton Method

  • Ko, Young-Don;Kim, Kil-Han;Yun, Il-Gu;Lee, Kyu-Bok;Kim, Jong-Kyu
    • Transactions on Electrical and Electronic Materials
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    • 제6권6호
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    • pp.256-261
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    • 2005
  • This paper presents that the modeling to predict the characteristics with respect to the performance of solenoid embedded inductors manufactured by LTCC process via the nonlinear regression model based on the quasi-Newton method. In order to reduce the runs, the design of experiments (DOE) was used to generate the design space. The nonlinear process models were constructed by the piecewise regression model based on the quasi-Newton method for estimating the model coefficient with the break point on the statistical confidence intervals. Those models were verified by the model accuracy checking based on the assumption statistically.

퍼지 제어규칙을 기반으로한 RBF 신경회로망 제어기 설계 (Design of RBF Neural Network Controller Based on Fuzzy Control Rules)

  • 최종수;권오신
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 하계학술대회 논문집 B
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    • pp.394-396
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    • 1997
  • This paper describes RBF network controller based on fuzzy control rules for intelligent control of nonlinear systems. The proposed scheme is derived from the functional equivalence between RBF networks and fuzzy inference systems. The design procedure of the proposed scheme is realized by first transforming the fuzzy control rules into the parameters of RBF networks. The optimized RBF network controller is then performed through the gradient descent learning mechanism to an error function. The proposed method is rigorously tested using a nonlinear and unstable nonlinear system. Simulation is performed to demonstrate the feasibility and effectiveness of the proposed scheme.

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