Multiaxial Fatigue Crack Orientation and Early Growth Investigation Considering the Nonproportional Loading

2018 ◽  
Vol 21 (4) ◽  
pp. 358-370 ◽  
Author(s):  
W. Song ◽  
X. Liu ◽  
F. Berto
Keyword(s):  
Fatigue Crack ◽  
Early Growth ◽  
Multiaxial Fatigue ◽  
Crack Orientation ◽  
Nonproportional Loading

Three-Dimensional Study of Fatigue Crack Growth in a Rotating Disc

2013 ◽  
Vol 3 (2) ◽  
pp. 45-62
Author(s):  
Eskandari Hadi ◽  
Nami Mohammad Rahim
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Crack Front ◽  
Numerical Technique ◽  
Three Dimensional ◽  
Crack Orientation ◽  
Rotating Disc ◽  
Mesh Density ◽  
Three Dimensional Finite Element

The problem of fatigue-crack-growth in a rotating disc at different crack orientation angles is studied by using an automated numerical technique, which calculates the stress intensity factors on the crack front through the three-dimensional finite element method. Paris law is used to develop the fatigue shape of initially semi-elliptical surface crack. Because of needs for the higher mesh density and accuracy near the crack, the sub-modeling technique is used in the analysis. The distribution of SIF’s along the crack front at each step of growth is studied and the effect of crack orientation on the rate of crack-growth is investigated. The calculated SIF’s are reasonable and could be used to predict the probable crack growth rates in fracture mechanics analysis and can help engineers to consider in their designing and to prevent any unwanted failure of such components.

scholarly journals A fatigue crack initiation and growth life estimation method in single-bolted connections

2019 ◽  
Vol 54 (2) ◽  
pp. 79-94 ◽  
Author(s):  
Arash P Jirandehi ◽  
TN Chakherlou
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Crack Initiation ◽  
Crack Growth ◽  
Fatigue Crack Initiation ◽  
Multiaxial Fatigue ◽  
Estimation Accuracy ◽  
Life Estimation ◽  
Lower Error ◽  
Fatigue Life Estimation

Fatigue life estimation accuracy of mechanical parts and assemblies has always been the source of concern in different industries. The main contribution of this article lies in a study on the accuracy of different multiaxial fatigue criteria, proposing and investigating the accuracy of four optimized fatigue crack initiation life estimation methods—volume, weighted volume, surface and point, thereby improving the multiaxial fatigue life estimation accuracy. In order to achieve the goal, the fatigue lives of bolt clamped specimens, previously tested under defined experimental conditions, were estimated during fatigue crack initiation and fatigue crack growth and then summed together. In the fatigue crack initiation part, a code was written and used in the MATLAB software environment based on critical plane approach and the different multiaxial fatigue criteria. Besides the AFGROW software was utilized to estimate the crack growth share of fatigue life. Experimental and numerical results showed to be in agreement. Furthermore, detailed study and comparison of the results with the available experimental data showed that a combination of Smith–Watson–Topper approach and volume method results in lower error values, while a combination of Fatemi–Socie criterion and surface or point method presents estimated lives with lower error values. In addition, the numerical proposed procedure resulted in a good prediction of the location of fatigue crack initiation.

A Theory for Fatigue Failure under Multiaxial Stress-Strain Conditions

1973 ◽  
Vol 187 (1) ◽  
pp. 745-755 ◽  
Author(s):  
M. W. Brown ◽  
K. J. Miller
Keyword(s):  
Experimental Data ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Failure ◽  
Physical Interpretation ◽  
Tensile Strain ◽  
Multiaxial Fatigue ◽  
Fatigue Data ◽  
Principal Strains

A new theory for multiaxial fatigue is presented that is based on a physical interpretation of the mechanisms of fatigue crack growth. It may be represented graphically by contours of constant life, which are expressed mathematically by where ε1, ε2 and ε3 are the principal strains, •ε1 ≥ ε2 ≥ ε3. This equation underlines the importance of strain parameters in correlating fatigue data. It illustrates the effect of both the shear strain and the tensile strain normal to the plane of maximum shear. The theory is compared with several classical and recent theories, which are briefly reviewed. It is shown that classical theories of fatigue failure cannot correlate experimental data, and may be dangerous if used for design purposes.

Fatigue Crack Growth Rate of 16mnr Steel with Effect of Stress Ratio

2010 ◽  
Vol 118-120 ◽  
pp. 278-282
Author(s):  
Dong Hui Yin ◽  
Xiao Gui Wang ◽  
Bao Xiang Qiu ◽  
Zeng Liang Gao
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stress Ratio ◽  
Unified Model ◽  
Multiaxial Fatigue ◽  
Cyclic Plasticity ◽  
Finite Element Software

Fatigue crack growth was simulated by using a newly developed unified model on the fatigue initiation and crack growth based on an incremental multiaxial fatigue criterion. The cyclic elastic-plastic stress-strain field was analyzed using the general-purpose finite element software (ABAQUS) with the implementation of a robust cyclic plasticity theory. The fatigue crack growth rates with respect to three different stress ratios were selected as the benchmark to check the unified model. The predicted results agreed with the experimental data very well. The insensitivity of the crack growth rate to the stress ratio is due to the fast mean stress relaxation.

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