• Title, Summary, Keyword: mode acceleration method

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Modal Analysis of Composite Trapezoidal Plates Undergoing In-plane Translational Acceleration (면내 병진 가속을 받는 복합재 사다리꼴 평판의 진동 해석)

  • Lim, Hong-Seok;Yoo, Hong-Hee
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.27 no.9
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    • pp.1486-1491
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    • 2003
  • A modeling method for the modal analysis of a composite trapezoidal plate undergoing in-plane translational acceleration is presented in this paper. The equations of motion for the plate are derived and transformed into a dimensionless form. The effects of the inclination angles, fiber orientation angle and the acceleration on the modal characteristics of the plate are investigated.

Vibration Characteristics of Cantilever Beam with a Crack (단일 크랙을 갖는 외팔보의 진동특성)

  • Kim, Jong-Do;Jo, Ji-Yun;Yoon, Moon-Chul
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.23 no.3
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    • pp.223-229
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    • 2014
  • In this paper, the natural frequency and damping ratio are analyzed with the acceleration signal of an Euler-Bernoulli beam using the impact hammer test. The results are presented according to crack depth and position using the recursive least squares method. The results are compared and investigated with FEM analysis of CATIA. Both methods agree well with each other regarding the natural mode characteristics. The captured acceleration can be used for the calculation of the natural frequency and damping ratio using time series methods that are based on the measured acceleration. Using these data, a recursive time series model with the acceleration signal was configured and the behaviors of the natural frequency and damping ratio were investigated and analyzed. Finally, the results can be used for the prediction of crack position and depth under different crack conditions for an Euler-Bernoulli beam.

Cooperative Guidance Law for Multiple Near Space Interceptors with Impact Time Control

  • Guo, Chao;Liang, Xiao-Geng
    • International Journal of Aeronautical and Space Sciences
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    • v.15 no.3
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    • pp.281-292
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    • 2014
  • We propose a novel cooperative guidance law design method based on the finite time disturbance observer (FTDO) for multiple near space interceptors (NSIs) with impact time control. Initially, we construct a cooperative guidance model with head pursuit, and employ the FTDO to estimate the system disturbance caused by target maneuvering. We subsequently separate the cooperative guidance process into two stages, and develop the normal acceleration command based on the super-twisting algorithm (STA) and disturbance estimated value, to ensure the convergence of the relative distance. Then, we also design the acceleration command along the line-of-sight (LOS), based on the nonsingular fast terminal sliding mode (NFTSM) control, to ensure that all the NSIs simultaneously hit the target. Furthermore, we prove the stability of the closed-loop guidance system, based on the Lyapunov theory. Finally, our simulation results of a three-to-one interception scenario show that the proposed cooperative guidance scheme makes all the NSIs hit the target at the same time.

Effects of ground motion scaling on nonlinear higher mode building response

  • Wood, R.L.;Hutchinson, T.C.
    • Earthquakes and Structures
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    • v.3 no.6
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    • pp.869-887
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    • 2012
  • Ground motion scaling techniques are actively debated in the earthquake engineering community. Considerations such as what amplitude, over what period range and to what target spectrum are amongst the questions of practical importance. In this paper, the effect of various ground motion scaling approaches are explored using three reinforced concrete prototypical building models of 8, 12 and 20 stories designed to respond nonlinearly under a design level earthquake event in the seismically active Southern California region. Twenty-one recorded earthquake motions are selected using a probabilistic seismic hazard analysis and subsequently scaled using four different strategies. These motions are subsequently compared to spectrally compatible motions. The nonlinear response of a planar frameidealized building is evaluated in terms of plasticity distribution, floor level acceleration and uncorrelated acceleration amplification ratio distributions; and interstory drift distributions. The most pronounced response variability observed in association with the scaling method is the extent of higher mode participation in the nonlinear demands.

Mode Analysis of Coupled System (커플시스템의 모우드 분석 연구)

  • Kim, Jong-Do;Yoon, Moon-Chul
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.9 no.3
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    • pp.28-34
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    • 2010
  • The suggested coupled system was analyzed using FRF and mode analysis. The eigen-mode of FRF analysis is consistent with that of conventional FFT in spectrum. Also, three numerical responses of second order system, which are coupled, was obtained using the Runge-Kutta Gill method. The displacement, velocity and acceleration response were calculated for the numerical analysis of coupled system and the displacement response was used for the calculation of FRF of this system. Using the mixed response of 1st and 2nd mode in example, the FRF was analysed for the analysis of mixed mode coupled system. Also, its mode shape was acquired by solving the eigen problem of coupled system.

Position Control of Induction Motor Using the Sliding Mode PID Control Method (슬라이딩 모드 PID 제어법을 이용한 유도 전동기의 위치제어)

  • Lee, Yoon-Jong;Kim, Hee-Jun;Son, Young-Dae;Jang, Bong-Jae
    • Proceedings of the KIEE Conference
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    • pp.341-345
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    • 1990
  • This paper presents the three section sliding mode control algorithm based on hysteresis current control add indirect field oriented control method, and applies it to the position control of induction motor. The three section sliding trajectories are defined in such a way that the system responds following a max acceleration line, then a max speed line, and finally a max deceleration line. This control scheme solves the problem of robustness loss during the reaching phase that occurs in conventional VSC strategy, and ensures the stable sliding mode and robustness enhancement throughout an entire response. Also, the PID controller operating in parallel is adopted to eliminate the sliding mode's collapse phenomenon near the origin caused by steady state chattering phenomenon Digital simulation results confirm that the dynamic performance of the system is insensitive to parameter variations and disturbances.

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Mode Analysis of Uncoupled System (언커플 시스템의 모우드 분석 연구)

  • Kim, Jong-Do;Yoon, Moon-Chul;Kim, Seon-Jin;Yang, Bo-Suk
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.9 no.3
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    • pp.35-41
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    • 2010
  • In this study, a mode analysis of uncoupled system was discussed using FRF. The eigen-mode range of FRF analysis is consistent with conventional FFT in spectrum. Also, the numerical response of second order uncoupled system was obtained using the Runge-Kutta Gill method. The displacement, velocity and acceleration response were calculated after numerical analysis and its response was used for the calculation of FRF for uncoupled system. Using the separated and mixed response of 1st and 2nd mode in example, its FRF was analysed for the prediction of the uncoupled systems and its mode shape was calculated by solving the eigen problem.

VSC with three-segment nonlinear sliding mode for robot manipulator (로봇 매니퓰레이터를 위한 삼분 비선형 슬라이딩 모드를 가지는 가변구조 제어)

  • 최성훈;전경한;최봉열
    • 제어로봇시스템학회:학술대회논문집
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    • pp.69-72
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    • 1996
  • In this paper robust tracking control scheme using the new three-segment nonlinear sliding mode technique for nonlinear rigid robotic manipulator is developed. Sliding mode consists of three segments, the promotional acceleration segment, the constant velocity segment and the deceleration segment using terminal sliding mode. Strong robustness and fast error convergence can be obtained for rigid robotic manipulators with large uncertain dynamics by using the new three-segment nonlinear sliding mode technique together with a few useful structural properties of rigid robotic manipulator. The efficiency of the proposed method for the tracking has been demonstrated by simulations for two-link robot manipulator.

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Parametric Modelling of Uncoupled System (언커플시스템의 파라메트릭 모델링)

  • Yoon, Moon-Chul;Kim, Jong-Do;Kim, Kwang-Heui
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.5 no.3
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    • pp.36-42
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    • 2006
  • The analytical realization of uncoupled system was introduced in this study using times series and its spectrum analysis. The ARMAX spectra of time series methods were compared with the conventional FFT spectrum. Also, the response of second order system uncoupled was solved using the Runge-Kutta Gill method. In this numerical analysis, the displacement, velocity and acceleration were calculated. The displacement response among them was used for the power spectrum analysis. The ARMAX algorithm in time series was proved to be appropriate for the mode estimation and spectrum analysis. Using the separate response of first and second mode, each modes were calculated separately and the response of mixed modes was also analyzed for the mode estimation using several time series methods.

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Occupant comfort evaluation and wind-induced serviceability design optimization of tall buildings

  • Huang, M.F.;Chan, C.M.;Kwok, Kenny C.S.
    • Wind and Structures
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    • v.14 no.6
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    • pp.559-582
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    • 2011
  • This paper presents an integrated wind-induced dynamic analysis and computer-based design optimization technique for minimizing the structural cost of general tall buildings subject to static and dynamic serviceability design criteria. Once the wind-induced dynamic response of a tall building structure is accurately determined and the optimal serviceability design problem is explicitly formulated, a rigorously derived Optimality Criteria (OC) method is to be developed to achieve the optimal distribution of element stiffness of the structural system satisfying the wind-induced drift and acceleration design constraints. The effectiveness and practicality of the optimal design technique are illustrated by a full-scale 60-story building with complex 3D mode shapes. Both peak resultant acceleration criteria and frequency dependent modal acceleration criteria are considered and their influences on the optimization results are highlighted. Results have shown that the use of various acceleration criteria has different implications in the habitability evaluations and subsequently different optimal design solutions. The computer based optimization technique provides a powerful tool for the lateral drift and occupant comfort design of tall building structures.