Fatigue Damage Modeling Approach Based on Evolutionary Power Spectrum Density

2019 ◽  
Author(s):  
Zhui Li ◽  
Ayhan Ince ◽  
Jean-Gabriel Lacombe
Keyword(s):  
Power Spectrum ◽  
Fatigue Damage ◽  
Power Spectrum Density ◽  
Damage Modeling ◽  
Evolutionary Power Spectrum ◽  
Modeling Approach ◽  
Spectrum Density

Direct Damage Evaluation Method for Thermal Fatigue Based on Power Spectrum Density Functions

2007 ◽  
Author(s):  
Shinsuke Sakai ◽  
Kei Honda ◽  
Satoshi Okajima ◽  
Satoshi Izumi ◽  
Naoto Kasahara
Keyword(s):  
Power Spectrum ◽  
Fatigue Damage ◽  
Thermal Fatigue ◽  
Temperature Fluctuation ◽  
Evaluation Method ◽  
Safety Margin ◽  
Amplitude Distribution ◽  
Power Spectrum Density ◽  
Damage Evaluation ◽  
Spectrum Density

At an incomplete mixing area of high and low temperature fluids, fluid temperature fluctuation often occurs. It induces cyclic thermal stresses in the wall, which may result in fatigue crack initiation. Kasahara et. al. proposed the thermal fatigue evaluation method based on power spectrum density (PSD) in PVP05. This method generalizes the evaluation procedure by preparing PSD charts of fluid and frequency transfer functions of stress for various kinds of plant components. From design point of view, however, this method is too complicated due to the inverse Fourier transform and wave decomposition procedures named Rain Flow Cycle Counting (RFC). In this paper, simplified damage evaluation method for thermal fatigue is proposed by directly evaluating fatigue damage from PSD of stress. Since analytical treatment for evaluation of fatigue amplitude distribution based on PSD is difficult due to complicated procedure of RFC, direct evaluation method for RFC amplitude distribution from PSD is newly proposed. This method gives fatigue damage evaluation with safety margin. This paper shows the dependency of safety margin on geometry of PSD. Finally, application to design for thermal fatigue will be shown. Since PSD of stress in the wall near temperature fluctuation can be easily evaluated using Kasahara’s method, the proposed method will make thermal fatigue damage evaluation far easier.

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

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.

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.

Sign in / Sign up

Export Citation Format

Share Document