Reliability Assessment on Thickness Effect in Fatigue Crack Growth

2005 ◽  
Vol 297-300 ◽  
pp. 1913-1918
Author(s):  
Seon Jin Kim ◽  
Yu Sik Kong ◽  
Sang Woo Kwon
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Random Fields ◽  
Crack Surface ◽  
Simulation Method ◽  
Thickness Effect ◽  
Specimen Thickness ◽  
Fatigue Crack Growth Life ◽  
Non Gaussian

The evaluation of specimen thickness effect of fatigue crack growth life by the simulation of probabilistic fatigue crack growth is presented. In this paper, the material resistance to fatigue crack growth is treated as a spatial stochastic process, which varies randomly on the crack surface. Using the previous experimental data, the non-Gaussian (eventually Weibull, in this report) random fields simulation method is applied. This method is useful to estimate the probability distribution of fatigue crack growth life and the variability due to specimen thickness by simulating material resistance to fatigue crack growth along a crack path.

On Characteristics of Weibull Distribution Parameters of Fatigue Crack Growth Lives

2004 ◽  
Vol 261-263 ◽  
pp. 1275-1280 ◽  
Author(s):  
Seon Jin Kim ◽  
Young Suk Kim ◽  
Sang Woo Kwon
Keyword(s):  
Fatigue Crack ◽  
Stress Intensity ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Probability Distributions ◽  
Simulation Method ◽  
Gaussian Random Fields ◽  
Specimen Thickness ◽  
Intensity Level ◽  
Non Gaussian

This paper illustrates the characteristics of parameters for three-parameter Weibull probability distribution of fatigue crack growth lives under constant stress intensity factor control experiments. Applying the statistical properties of the previous experimental results, the fatigue crack curves were simulated by using the non-Gaussian random fields simulation method and analyzed for the different specimen thickness and stress intensity level to determine the probability distributions of the fatigue crack growth life.

Modeling and calculation of the fatigue crack growth life in structural steels

2021 ◽  
Vol 87 (4) ◽  
pp. 43-51
Author(s):  
A. N. Savkin ◽  
K. A. Badikov ◽  
A. A. Sedov
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Closure ◽  
Maximum Load ◽  
Good Convergence ◽  
Calculation Results ◽  
Fatigue Crack Growth Life ◽  
Kinetics Of ◽  
Irregular Loading

The kinetics of fatigue crack growth has been studied in tensile testing of compact steel tensile specimens (S(T)-type) in the middle section of the kinetic diagram of fatigue fracture (fatigue crack growth diagram) under regular and irregular loading with different asymmetry and maximum load values. The samples were tested on a BISS Nano-25kN servo-hydraulic machine. Standard loading spectra typical for different technical objects exposed to alternating loading during operation were used. The values of the crack growth rate per cycle in the loading block were obtained. Parameters for assessing the character of irregular loading and crack closure, namely, the irregularity factor and crack closure coefficient were proposed. When calculating the effective value of the range of the stress intensity factor (SIF) at the crack mouth, we propose also to take into account the loading irregularity in addition to the closure coefficient. With this approach, the obtained fatigue crack growth diagrams can be grouped into one equivalent curve, which is characteristic of regular loading with R = 0. Moreover, grouping of the fatigue crack growth diagrams provided the use of unified parameters when calculating the crack growth kinetics, regardless of the type and parameters of loading, which rather simplified the crack growth determination. The fatigue crack growth life was predicted taking into account the crack «closure» and the nature of loading according both to the approach developed by the authors and by cyclic calculation method (cycle-by-cycle). All the data obtained are tabulated and classed according to the type of loading. The calculation results and experimental data showed good convergence, which was confirmed by the high values of the correlation coefficient.

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