Calculation of extreme accelerations in earthquake motion due to ground spalling

The response of a large-size cooling tower with 250m high subjected to the seismic action are investigated by both random vibration theory and response spectrum method. Shell element is taken to model the tower body, and beam element is used for the circular foundation and supporting columns. The earthquake motion input is a colored filtered white noise model and mode superposition method is adopted to analyze the random response of the large-size cooling tower. The paper presents the power spectrum density functions (PDF) and standard deviation of the displacement of the top and characteristic node, and the analysis results indicate that the results of the stationary random vibration theory and the response spectrum method are the same order of magnitude. The power spectrum density function of the bottom node stress is obviously bigger than the one at the top and the throat, and the random response of meridonal stress is dominated at the top. In addition, the peak frequency position of the power spectrum density function is different from the corresponding stress.

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FUNDAMENTAL STUDY ON PULSE-TYPE EARTHQUAKE MOTION NEAR SEISMIC FAULT BASED ON DYNAMIC RUPTURE MODEL

AIJ Journal of Technology and Design ◽

10.3130/aijt.21.83 ◽

2015 ◽

Vol 21 (47) ◽

pp. 83-88

Author(s):

Masayuki NAGANO ◽

Ryo UEDA ◽

Kenichi KATO ◽

Yasuhiro OTSUKA ◽

Kazuhito HIKIMA ◽

...

Keyword(s):

Dynamic Rupture ◽

Fundamental Study ◽

Seismic Fault ◽

Earthquake Motion ◽

Dynamic Rupture Model ◽

Pulse Type ◽

Rupture Model

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Parametric Instability in Metallic Bellows Subjected to Seismic Excitation

Volume 5: 22nd International Conference on Design Theory and Methodology; Special Conference on Mechanical Vibration and Noise ◽

10.1115/detc2010-28157 ◽

2010 ◽

Author(s):

Nobuyuki Kobayashi ◽

Keisaku Kitada ◽

Yoshiki Sugawara

Keyword(s):

Parametric Instability ◽

Fluid Pressure ◽

Element Model ◽

Frequency Component ◽

Seismic Excitation ◽

Axial Stiffness ◽

Predominant Frequency ◽

Earthquake Motion ◽

Static Fluid ◽

Stiffness Variation

This paper investigates the parametric instability of a metallic bellows filled with fluid and subjected to the variance of dynamic internal pressure due to an earthquake. The axial stiffness of the bellows varies due to the variation in internal static fluid pressure, and this stiffness variation induces a parametric instability in the bellows. A finite element model describing a bellows connected to a pipe is developed to examine the question of whether parametric instability is excited in such bellows by earthquake motion, which is not the harmonic vibration. Numerical simulations and experiments were carried out using the acceleration recorded by past recorded actual earthquakes. We find that indeed parametric instability may appear in the bellows when the natural frequency of the pipe is close to the predominant frequency component of the earthquake, though the earthquake motion is not harmonic.

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On the Efficacy of Magnetorheological Dampers for Seismic Response Reduction

Volume 1B: 16th Biennial Conference on Mechanical Vibration and Noise ◽

10.1115/detc97/vib-3828 ◽

1997 ◽

Author(s):

S. J. Dyke ◽

B. F. Spencer ◽

M. K. Sain ◽

J. D. Carlson

Keyword(s):

Control Systems ◽

Structural Response ◽

Mr Damper ◽

Seismic Protection ◽

Seismic Excitations ◽

One Dimensional ◽

Mr Dampers ◽

Earthquake Motion ◽

Intrinsic Nonlinearity ◽

Series Of Experiments

Abstract In this paper, the efficacy of magnetorheological (MR) dampers for seismic protection of structures is investigated through a series of experiments in which an MR damper is used to control a three story test structure subjected to a one-dimensional earthquake motion. Because of the intrinsic nonlinearity of the MR damper, several earthquake amplitudes are considered to investigate the performance, in terms of both peak and rms responses, of this control systems over a range of loading conditions. The results indicate that the MR damper is quite effective for structural response reduction over a wide class of seismic excitations.

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