Different Fatigue Dynamics Under Statistically and Spectrally Similar Deterministic and Stochastic Excitations

2013 ◽  
Vol 81 (4) ◽  
Author(s):  
Son Hai Nguyen ◽  
Mike Falco ◽  
Ming Liu ◽  
David Chelidze
Keyword(s):  
Crack Growth ◽  
Fatigue Damage ◽  
Damage Accumulation ◽  
Growth Dynamics ◽  
Experimental System ◽  
Counting Method ◽  
Random Loading ◽  
Stochastic Excitations ◽  
Fatigue Damage Accumulation ◽  
System Coupling

Estimating and tracking crack growth dynamics is essential for fatigue failure prediction. A new experimental system—coupling structural and crack growth dynamics—was used to show fatigue damage accumulation is different under chaotic (i.e., deterministic) and stochastic (i.e., random) loading, even when both excitations possess the same spectral and statistical signatures. Furthermore, the conventional rain-flow counting method considerably overestimates damage in case of chaotic forcing. Important nonlinear loading characteristics, which can explain the observed discrepancies, are identified and suggested to be included as loading parameters in new macroscopic fatigue models.

Characterization of Fatigue Dynamics Under Deterministic and Stochastic Excitation

2012 ◽  
Author(s):  
Son Hai Nguyen ◽  
Mike Falco ◽  
Ming Liu ◽  
David Chelidze
Keyword(s):  
Crack Growth ◽  
Model Development ◽  
Growth Dynamics ◽  
Experimental System ◽  
Stochastic Excitation ◽  
Counting Method ◽  
Fatigue Damage Accumulation ◽  
Stochastic Loading ◽  
System Coupling

Estimating and tracking dynamics of crack growth is essential for fatigue failure prediction. A new experimental system coupling structural and crack growth dynamics was used to show fatigue damage accumulation is different under chaotic and stochastic loading, even when both excitations have similar spectral and statistical signatures. Furthermore, conventional rain-flow counting method considerably overestimates damage in case of chaotic forcing. Important nonlinear loading characteristics are identified to guide the new fatigue model development.

Probabilistic Prediction of Crack Growth Based on Creep/Fatigue Damage Accumulation Mechanism

2011 ◽  
Vol 8 (5) ◽  
pp. 103690 ◽  
Author(s):  
Zhigang Wei ◽  
Fulun Yang ◽  
Henry Cheng ◽  
Kamran Nikbin ◽  
A. Saxena ◽  
...  
Keyword(s):  
Crack Growth ◽  
Fatigue Damage ◽  
Damage Accumulation ◽  
Probabilistic Prediction ◽  
Fatigue Damage Accumulation ◽  
Creep Fatigue ◽  
Accumulation Mechanism

Nonlinear Fatigue Damage Accumulation Under Random Loading

1996 ◽  
Vol 118 (2) ◽  
pp. 168-173 ◽  
Author(s):  
W. Q. Zhu ◽  
M. X. Jiang
Keyword(s):  
Fatigue Damage ◽  
Damage Accumulation ◽  
Stochastic Theory ◽  
Reliability Function ◽  
Random Loading ◽  
Fatigue Damage Accumulation ◽  
Probability Densities ◽  
Cumulative Fatigue Damage ◽  
Analytical Expressions ◽  
Damage Rule

The analytical expressions for the probability densities of the cumulative fatigue damage and fatigue life and for the reliability function are obtained for a mechanical or structural component subject to stationary random stress process on the basis of a stochastic theory of fatigue damage accumulation proposed by the first author and his co-worker and the Morrow’s nonlinear damage rule. The comparison between the results from Morrow’s and Palmgren-Miner’s damage rules for the case when the stress is a narrow-band stationary Gaussian process with zero mean is made and some important conclusions are drawn.

A CRACK GROWTH MODEL BASED ON FATIGUE DAMAGE ACCUMULATION

2010 ◽  
Vol 24 (15n16) ◽  
pp. 2774-2779 ◽  
Author(s):  
BAOXIANG QIU ◽  
XIAOGUI WANG ◽  
ZENGLIANG GAO
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Damage ◽  
Growth Model ◽  
Damage Accumulation ◽  
Fatigue Damage Accumulation ◽  
Crack Growth Model

A novel model for predicting the fatigue crack growth had been developed based on the concept of the fatigue damage accumulation. Fatigue crack growth was considered as a process of continuous crack nucleation. The crack tip failed to form a fresh crack while the accumulative fatigue damage reached the critical damage. A simplified model of the general crack growth model was proposed with the assumption that the damage zone can be divided into many different zones and each zone had the same crack growth rate. The model was applied to predict the crack growth of the compact specimen made of 16MnR steel under the constant amplitude loading. The predicted crack growth rate was in excellent agreement with the experimental observations.

Fatigue damage accumulation around notches

2004 ◽  
Vol 46 (6) ◽  
pp. 309-313
Author(s):  
Yutaka Iino ◽  
Hideo Yano
Keyword(s):  
Fatigue Damage ◽  
Damage Accumulation ◽  
Fatigue Damage Accumulation
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