• Title/Summary/Keyword: Dynamic load transfer function

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Characteristics of Dynamic Load Transfer for Vertically Vibrating Pile (연직진동말뚝의 동적 하중전이 특성)

  • Lee, Seung-Hyun;Kim, Eung-Seok;Yoon, Ki-Yong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.15 no.6
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    • pp.3872-3878
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    • 2014
  • In this study, the dynamic load transfer function, which is necessary for analyzing a pile installed by a vibro hammer, was determined by comparing the results of the analyses and instrumented tests. The static load transfer function was modeled by the Ramberg-Osgood model through an analytical method before determining the dynamic load transfer curve. The parameters of the Ramberg-Osgood model were correlated with the N value of the standard penetration test and average values of the correlation coefficient were 0.97 for the shaft load transfer and 0.98 for the base load transfer. The dynamic load transfer function was simulated using the modified Ramberg-Osgood model. The results showed that there were little differences in the characteristics of dynamic load transfer between the results of the measurement and prediction.

Study of the dynamic characteristics of a hydraulic power supply (유압공급장치의 동특성에 관한 연구)

  • 이성래
    • 제어로봇시스템학회:학술대회논문집
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    • 1993.10a
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    • pp.1172-1177
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    • 1993
  • Dynamic characteristics of a hydraulic power supply are studied theoretically and computationally. The transfer function between the supply pressure and the load flow is derived considering relief valve dynamics, accumulator dynamics, and flow line dynamics. Frequency responses and time responses are obtained in many conditions using the transfer function and nonlinear mathematical model respectively.

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Dynamic Characteristics Control of a Step-down Chopper Using Load current Feed-forward Compensator (부하전류 전향보상기를 이용한 강압쵸퍼의 동특성 제어)

  • Chung, Chun-Byung;Chun, Ji-Yong;Jeon, Kee-Young;Han, Kyung-Hee
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2008.05a
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    • pp.66-69
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    • 2008
  • In this paper, The author present a load current feed-forward compensator by method that improve voltage controller of Step-down Chopper to get stable output voltage to sudden change of load current. To confirm the characteristicsof a presented load current feed -forward compensator compared each transfer function of whole system that load current feed-forward compensator is added with transfer function of whole system that existent voltage controller is included using Mason gains formula in Root locus and Bode diagram. As a result the pole of system is improved, extreme point of the wave and system improves, and size of peak value and phase margin of break frequency in resonance frequency confirmed that is good. Therefore, presented control technique could confirm that reduce influence by perturbation and improves stationary state and dynamic characteristics in output of Step-down Chopper.

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Estimation of Dynamic Load of the Utility in Building by TPA Method (TPA 기법을 이용한 건물 내 설비 동하중 산정)

  • Jeong, Min-Ki;Lee, Seong-Soo;Kim, Yong-Ku;Ahn, Sang-Kyung;Lee, Sang-Yeop
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.19 no.8
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    • pp.773-780
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    • 2009
  • The facility equipments generate dynamic force on building floor and the force can be measured with force transducer. However, this method depends on the measuring capacity or range of sensor, or mounts installation condition of equipments. Because of this restricting condition on force measuring system, this paper suggests a indirect method, the TPA(transfer path analysis) method, that produces a closely approximate dynamic force of equipments. This method calculates the dynamic force by using transfer response function. Firstly, the calculated dynamic force of impact load and continuous load was respectively compared with the sensor-measured value to examine the accuracy of TPA method. After that, the dynamic force and response induced by large facility equipments - a cooling tower, AHU and a large ventilator - were calculated by TPA method and the validity of these value were examined.

Estimation of the Dynamic Load of the Utility in Building by TPA Method (TPA 기법을 이용한 건물 내 설비 동하중 산정)

  • Jeong, Min-Ki;Kim, Yong-Ku;Ahn, Sang-Kyung;Lee, Sang-Yeop;Lee, Seong-Soo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.11a
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    • pp.452-457
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    • 2008
  • In this paper, the vibrations of floor systems of which buildings are under construction are studied by experimental and analysis method. The first step is to measure the operational response data and FRF at the supporting points of the utility and the second step is to calculate the dynamic load by TPA Method which provided by LMS VirtualLab System Analysis Module. The dynamics we used to identify is expressed by below equation; $$\{F_{oper}\}=[H]^{-1}\;{\cdot}\;\{{.. \atop x_{oper}}\}$$ Where, H(Transfer function between position of the force and response) and x(response) are measured by vibration test.

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A Study on Determining Complex Young's Modulus of Acoustic Materials (음향 재질의 복소수 모듈러스 추출에 관한 연구)

  • Kim, In-Su;Lee, Hyo-Keun;Kim, Sung-Hee
    • The Journal of the Acoustical Society of Korea
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    • v.10 no.1
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    • pp.30-36
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    • 1991
  • Since the Complex Young's Modulus of acoustic materials is a function of frequency under a static load, a cylindrical specimen modelled by rod-like one with losses is used to determine the dynamic characteristics of materials. The specimen is excited into longitudinal vibration at its one end by shaker and at the other end, loaded by a mass corresponding to the desired static load and thus the transfer function of specimen is measured. This transfer function method is analyzed theoretically and experimentally over a frequency range of 50 Hz to 20 KHz. The analysis includes the measurability of the transfer function, the frequency range of the method and lateral motion effect.

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The Effect of Load Impedances on the Frequency Response of Pressure Propagation in the Pneumatic Transmission Line (기체 전달 관로에 있어서 압력 전파의 주파수 응답에 대한 부하 임피던스의 영향)

  • Yoon, S.J.;Son, B.J.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.6 no.4
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    • pp.344-353
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    • 1994
  • This study numerically analyzed the dynamic characteristics of the frequency response on the pneumatic transmission line with load impedances. The pressure transfer function is represented by the distributed parameter line model. To validate the mathematical approximations of Bessel function ratios, the results of frequency response in a blocked line were compared with those obtained by the Infinite-product, Brown's and Square-root approximations. Special emphasis was given to the frequency response characteristics on the pneumatic transmission line with load impedances. Computations were carried out for the wide range of parameters in terms of load capacitance ratio and load resistance ratio. The present results indicated that the theoretical model is capable of accurately predicting the frequency response characteristics for any configuration of a fluid transmission line.

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A NARX Dynamic Neural Network Platform for Small-Sat PDM (동적신경망 NARX 기반의 SAR 전력모듈 안전성 연구)

  • Lee, Hae-Jun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.24 no.6
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    • pp.809-817
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    • 2020
  • In the design and development process of Small-Sat power distribution and transmission module, the stability of dynamic resources was evaluated by a deep learning algorithm. The requirements for the stability evaluation consisted of the power distribution function of the power distribution module and demand module to the SAR radar in Small-Sat. To verify the performance of the switching power components constituting the power module PDM, the reliability was verified using a dynamic neural network. The adoption material of deep learning for reliability verification is the power distribution function of the payload to the power supplied from the small satellite main body. Modeling targets for verifying the performance of this function are output voltage (slew rate control), voltage error, and load power characteristics. First, to this end, the Coefficient Structure area was defined by modeling, and PCB modules were fabricated to compare stability and reliability. Second, Levenberg-Marquare based Two-Way NARX neural network Sigmoid Transfer was used as a deep learning algorithm.

Dynamic Characteristics Improvement of a Step-Down Chopper Using Load Current Feed-Forward Compensator (부하전류 전향보상기를 이용한 강압쵸퍼의 동특성 항상)

  • Chun, Ji-Young;Jeon, Kee-Young;Chung, Chun-Byung;Han, Kyung-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.22 no.12
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    • pp.29-35
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    • 2008
  • In this paper, The author present a load current feed-forward compensator by method that improve voltage controller of Step-down Chopper to get stable output voltage to sudden change of load current. To confirm the characteristics of a presented load current feed-forward compensator compared each transfer function of whole system that load current feed-forward compensator is added with transfer function of whole system that existent voltage controller is included using Mason gains formula in Root locus and Bode diagram. As a result the pole of system is improved, extreme point of the wave and system improves, and size of peak value and phase margin of break frequency in resonance frequency confirmed that is good. Therefore, presented control technique could confirm that reduce influence by perturbation and improves stationary state and dynamic characteristics in output of Step-down Chopper.

A Study on the Dynamic Characteristics of a Turbocharged Diesel Engine (터보 과급 디젤 기관의 동특성에 관한 연구)

  • Choi, N.J.;Lee, C.S.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.3 no.1
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    • pp.143-154
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    • 1995
  • This study investigates the response characteristics of a four-cylinder four-stroke turbocharged diesel engine by using computer simulation and experiments when a rapid acceleration is applied to the fuelpump rack. In the theoretical analysis, linearization method is used to avoid the difficulty on the complex nonlinear functions. Comppressor exit pressure, pressure and temperature of turbine inlet, and turbocharger speed are chosen as the independent variables of transfer functions which represent the dynamic characteristics of the turbocharger system, and expressed as the functions with respect to the time. Experiments on the same eigine system are also carried out to prove the validity of theoretical study. Further, this study carried an experiment for improving transient response performance by injecting air into the inlet manifold under the rapid accelerating conditions. The effects of air injection on the response performances are also represented at varying conditions such as injection pressure, injection period, accelerating rate, accelerating time, engine speed and load.

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