Random Response Analysis of a Large-Size Cooling Tower Subjected to the Stationary Earthquake Motion

2013 ◽  
Vol 423-426 ◽  
pp. 1589-1593
Author(s):  
Jia Ning Zhu ◽  
Ya Zhou Xu ◽  
Guo Liang Bai ◽  
Rui Wen Li
Keyword(s):  
Power Spectrum ◽  
Random Vibration ◽  
Cooling Tower ◽  
Response Spectrum ◽  
Power Spectrum Density ◽  
Random Response ◽  
Large Size ◽  
Earthquake Motion ◽  
Spectrum Density ◽  
Random Vibration Theory

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.

scholarly journals Vehicle Vibration Analysis in Changeable Speeds Solved by Pseudoexcitation Method

2010 ◽  
Vol 2010 ◽  
pp. 1-14 ◽  
Author(s):  
Li-Xin Guo ◽  
Li-Ping Zhang
Keyword(s):  
Numerical Simulation ◽  
Power Spectrum ◽  
Traditional Method ◽  
Vibration Analysis ◽  
Random Vibration ◽  
Degrees Of Freedom ◽  
Rear Wheel ◽  
Front Wheel ◽  
Power Spectrum Density ◽  
Spectrum Density

The vehicle driving comfort has become one of the important factors of vehicle quality and receives increasing attention. In this paper, the mechanical and mathematical models of the half-car, five degrees of freedom (DOF) of a vehicle were established, as well as the pseudoexcitation model of road conditions for the front wheel and the rear wheel. By the pseudoexcitation method, the equations of transient response and power spectrum density were established. After numerical simulation to vehicle vibration response of changeable driving, the results show that the pseudoexcitation method is more convenient than the traditional method and effectively solves the smoothness computation problems of vehicles while the pseudoexcitation method is used to analyze vehicle vibration under nonstationary random vibration environments.

Design Method of Power Spectrum Density Profile for Random Vibration Test Based upon S-N Curve

2008 ◽  
Author(s):  
Hiroyuki Usuda ◽  
Yutaka Ishikawa ◽  
Nobutaka Nakamura ◽  
Poritosh Roy ◽  
Daisuke Nei ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Density Profile ◽  
Random Vibration ◽  
Design Method ◽  
Power Spectrum Density ◽  
Vibration Test ◽  
Spectrum Density

The Modification Method of the Matlab Built-in Function PSD Using in the Field of Random Vibration

2011 ◽  
Vol 382 ◽  
pp. 220-223
Author(s):  
An Xu ◽  
Ruo Hong Zhao
Keyword(s):  
Power Spectrum ◽  
Random Vibration ◽  
Power Spectrum Density ◽  
Random Signal ◽  
Modification Method ◽  
Spectrum Density

The process of calculating power spectrum density is introduced. The built fuction PSD in Matlab used in engineering field widely is analyzed in detail. Problems are found when built-in function psd is used to calculated power spectrum density of random signal. Based on such analysis a modification method is proposed.

Orientation holes positioning of printed board based on LS-Power spectrum density algorithm

2018 ◽  
Vol 35 (3-4) ◽  
pp. 277-288
Author(s):  
Xiaxia ZENG ◽  
Zhenhua SONG ◽  
Wenzhong LIN ◽  
Haibo LUO
Keyword(s):  
Power Spectrum ◽  
Power Spectrum Density ◽  
Spectrum Density

The Time Domain Simulation of Non-Stationary Road Roughness

2013 ◽  
Vol 423-426 ◽  
pp. 1238-1242
Author(s):  
Hao Wang ◽  
Xiao Mei Shi
Keyword(s):  
Power Spectrum ◽  
Time Domain ◽  
Ride Comfort ◽  
Time History ◽  
Random Excitation ◽  
Power Spectrum Density ◽  
The Road ◽  
Road Roughness ◽  
Spectrum Density ◽  
History Of

The input of road roughness, which affects the ride comfort and the handling stability of vehicle, is the main excitation for the running vehicle. The time history of the road roughness was researched with the random phases, based on the stationary power spectrum density of the road roughness determined by the standards. Through the inverse Fourier transform, the random phases can be used to get the road roughness in time domain, together with the amplitude. Then, the time domain simulation of the non-stationary random excitation when the vehicle ran at the changing speed, would also be studied based on the random phases. It is proved that the random road excitation for the vehicle with the changing speed is stationary modulated evolution random excitation, and its power spectrum density is the stationary modulated evolutionary power spectrum density. And the numerical results for the time history of the non-stationary random inputs were also provided. The time history of the non-stationary random road can be used to evaluate the ride comfort of the vehicle which is running at the changing speed.

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