• Title, Summary, Keyword: mode acceleration method

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A Study on the Characteristics of PCN-PZT Piezoelectric Acceleration Sensor (PCN-PZT 압전형 가속도센서의 특성에 관한 연구)

  • Kim, Yeong-Deok;Kim, Gwang-Il;Jeong, U-Cheol;Go, Jae-Seok
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.5
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    • pp.354-360
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    • 1999
  • PCN-PZT piezoelectric acceleration sensors of annular shear mode voltage type were fabricated and their characteristics have been investigated. Field tests are also carried out. To avoid noise problems from the environmental conditions, acceleration sensors employed solid state micro-electronics for pre-amplifier. The calibration procedures based on the principle of the comparison method were adopted for investigating the characteristics of fabricated acceleration sensors. The voltage sensitivity and resonant frequency of fabricated acceleration sensors were 83mv/g, 23kHz, respectively. The lower and upper frequency limit were 4Hz and 9kHz, respectively. The variation of the voltage sensitivity showed 10% at $-406{\circ}C\; and\; 9%\; at\; 121^{\circ}C$ compared to that of reference temperature at $40^{\circ}C$.

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Generalized complex mode superposition approach for non-classically damped systems

  • Chen, Huating;Liu, Yanhui;Tan, Ping
    • Structural Engineering and Mechanics
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    • v.73 no.3
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    • pp.271-286
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    • 2020
  • Passive control technologies are commonly used in several areas to suppress structural vibrations by the addition of supplementary damping, and some modal damping may be heavy beyond critical damping even for regular structures with energy dissipation devices. The design of passive control structures is typically based on (complex) mode superposition approaches. However, the conventional mode superposition approach is predominantly applied to cases of under-critical damping. Moreover, when any modal damping ratio is equal or close to 1.0, the system becomes defective, i.e., a complete set of eigenvectors cannot be obtained such that some well-known algorithms for the quadratic eigenvalue problem are invalid. In this paper, a generalized complex mode superposition method that is suitable for under-critical, critical and over-critical damping is proposed and expressed in a unified form for structural displacement, velocity and acceleration responses. In the new method, the conventional algorithm for the eigenvalue problem is still valid, even though the system becomes defective due to critical modal damping. Based on the modal truncation error analysis, modal corrected methods for displacement and acceleration responses are developed to approximately consider the contribution of the truncated higher modes. Finally, the implementation of the proposed methods is presented through two numerical examples, and the effectiveness is investigated. The results also show that over-critically damped modes have a significant impact on structural responses. This study is a development of the original complex mode superposition method and can be applied well to dynamic analyses of non-classically damped systems.

Dynamic Response of Cantilevered Beams Subjected to a Travelling Mass with a Constant Acceleration (일정 가속 주행질량에 의한 외팔보의 동적응답)

  • 류봉조;윤충섭;김희중;이규섭
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.320-325
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    • 2004
  • The paper deals with the dynamic response of a cantilevered beam under a travelling mass with constant acceleration. Governing equations of motion taking into account all inertia effects of the travelling mass are derived by Galerkin's mode summation method, and Runge-Kutta integration method is applied to solve the differential equations. The effects of the speed, acceleration and the magnitude of the travelling mass on the response of the beam are fully investigated. A variety of numerical results allows us to draw important conclusions for structural design purposes.

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Fast Simulation of Output Voltage for High-Shock Piezoresistive Microaccelerometer Using Mode Superposition Method and Least Square Method (모드중첩법 및 최소자승법을 통한 고충격 압저항 미소가속도계의 출력전압 해석)

  • Han, Jeong-Sam;Kwon, Ki-Beom
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.36 no.7
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    • pp.777-787
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    • 2012
  • The transient analysis for the output voltage of a piezoresistive microaccelerometer takes a relatively high computation time because at least two iterations are required to calculate the piezoresistive-structural coupled response at each time step. In this study, the high computational cost for calculating the transient output voltage is considerably reduced by an approach integrating the mode superposition method and the least square method. In the approach, data on static displacement and output voltage calculated by piezoresistive-structural coupled simulation for three acceleration inputs are used to develop a quadratic regression model, relating the output voltage to the displacement at a certain observation point. The transient output voltage is then approximated by a regression model using the displacement response cheaply calculated by the mode superposition method. A high-impact microaccelerometer subject to several types of acceleration inputs such as 100,000 G shock, sine, step, and square pulses are adopted as a numerical example to represent the efficiency and accuracy of the suggested approach.

Modal Analysis of a Large Truss for Structural Integrity (건전성 평가를 위한 대형 트러스 구조물의 모드분석)

  • Park, Soo-Yong
    • Journal of Navigation and Port Research
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    • v.32 no.3
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    • pp.215-221
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    • 2008
  • Dynamic characteristics of a structure, i.e., natural frequency and mode shape, have been widely using as an input data in the area of structural integrity or health monitoring which combined with the damage evaluation and structural system identification techniques. It is very difficult, however, to get those information by the conventional modal analysis method from large structures, such as the offshore structure or the long-span bridge, since the source of vibration is not available. In this paper, a method to obtain the frequencies and the mode shapes of a large span truss structure using only acceleration responses is studied. The calculation procedures to obtain acceleration responses and frequency response functions are provided utilizing a numerical model of the truss, and the process to extract natural frequencies and mode shapes from the modal analysis is cleary explained. The extracted mode shapes by proposed method are compared with those from eigenvalue analysis for the estimation of accuracy. The validity of the mode shapes is also demonstrated using an existing damage detection technique for the truss structure by simulated damage cases.

Saturated Sliding Mode Control of SDOF System under Earthquake Leadings (지진을 받는 단자유도 진동계의 포화 슬라이딩 모드 제어)

  • 민경원;이상현;이영철;이승준;박민규
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.477-484
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    • 2003
  • Recently, sliding mode control(SMC) method has been investigated for control of building structures under earthquake loadings. SMC keeps responses of a structure in sliding surface while the structure is stable. This control method uses both linear controller and nonlinear controller such as bang-bang controller. This paper presents vibration control of a structure using saturated sliding mode controller, whose maximum conrtol force is limited. The effectiveness of SMC method with controler saturation is investigated based on two performance evaluation criteria: root mean square(RMS) and maximum values of floor drifts and accelerations. Simulation results indicate that SMC method is effective in reduction of displacement and acceleration utilizing the saturated controller's capacity efficiently.

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A Study for Detecting Fuel-cut Driving of Vehicle Using GPS (GPS를 이용한 차량 연료차단 관성주행의 감지에 관한 연구)

  • Ko, Kwang-Ho
    • Journal of Digital Convergence
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    • v.17 no.11
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    • pp.207-213
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    • 2019
  • The fuel-cut coast-down driving mode is activated when the acceleration pedal is released with transmission gear engaged, and it's a default function for electronic-controlled engine of vehicles. The fuel economy becomes better because fuel injection stops during fuel-cut driving mode. A fuel-cut detection method is suggested in the study and it's based on the speed, acceleration and road gradient data from GPS sensor. It detects fuel-cut driving mode by comparing calculated acceleration and realtime acceleration value. The one is estimated with driving resistance in the condition of fuel-cut driving and the other is from GPS sensor. The detection accuracy is about 80% when the method is verified with road driving data. The result is estimated with 9,600 data set of vehicle speed, acceleration, fuel consumption and road gradient from test driving on the road of 12km during 16 minutes, and the road slope is rather high. It's easy to detect fuel-cut without injector signal obtained by connecting wire. The detection error is from the fact that the variation range of speed, acceleration and road gradient data, used for road resistance force, is larger than the value of fuel consumption data.

Modal Analysis of Curved Beam. (곡선보의 모우드 해석)

  • 김영문;유기표
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.349-354
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    • 2000
  • The modal analysis based on deformations is the method to drived dynamic responsed from superposition of natural frequency and mode shape. In order to free vibration analysis of the structures, Aluminum-made model is used in experiment. The dynamic characteristic of the structures are determined from acceleration measurements using impulse hammer. Experimenrt input and output signal are derive from impact hammer and the one accerometer. This paper present three methods for calculating the natural frequencies and mode shapes of the structure with theory value and finite element analysis, experiment. The results were good approximated about natural frequency and mode shape.

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Dynamic Stability Analysis of an Axially Accelerating Beam Structure (축 방향 가속을 받는 보 구조물의 동적 안정성 해석)

  • Eun, Sung-Jin;Yoo, Hong-Hee
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.9
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    • pp.1053-1059
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    • 2005
  • Dynamic stability of an axially accelerating beam structure is investigated in this paper. The equations of motion of a fixed-free beam are derived using the hybrid deformation variable method and the assumed mode method. Unstable regions due to periodical acceleration are obtained by using the Floquet's theory. Stability diagrams are presented to illustrate the influence of the dimensionless acceleration, amplitude, and frequency. Also, buckling occurs when the acceleration exceeds a certain value. It is found that relatively large unstable regions exist around the first bending natural frequency, twice the first bending natural frequency, and twice the second bending natural frequency. The validity of the stability diagram is confirmed by direct numerical integration of the equations of motion.

Dynamic Stability Analysis of an Axially Accelerating Beam Structure (축 방향 가속을 받는 보 구조물의 동적 안정성 해석)

  • Eun, Sung-Jin;Yoo, Hong-Hee
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.877-882
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    • 2005
  • Dynamic stability of an axially accelerating beam stucture is investigated in this paper. The equations of motion of a fixed-free beam are derived using the hybrid deformation variable method and the assumed mode method. Unstable regions due to periodical acceleration are obtained by using the Floquet's theory. Stability diagrams are presented to illustrate the influence of the dimensionless acceleration, amplitude, and frequency. Also, buckling occurs when the acceleration exceeds a certain value. It is found that relatively targe unstable regions exist around the first bending natural frequency, twice the first bending natural frequency, and twice the second bending natural frequency. The validity of the stability diagram is confirmed by direct numerical integration of the equations of motion.

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