Mixed mode (I + II, I + III) fatigue crack growth rate description in P355NL1 and 18G2A steel using new energy parameter based on J-integral approach

2019 ◽  
Vol 99 ◽  
pp. 263-272 ◽  
Author(s):  
G. Lesiuk
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Mixed Mode ◽  
Energy Parameter ◽  
Integral Approach ◽  
J Integral ◽  
New Energy

Simulation of Fatigue Initiation and Non-Self-Similar Fatigue Crack Growth under Mixed Mode I/II Loading

2012 ◽  
Vol 224 ◽  
pp. 303-306
Author(s):  
Chen Chen Ma ◽  
Xiao Gui Wang
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Mixed Mode ◽  
Mode I ◽  
Fatigue Initiation ◽  
Self Similar ◽  
Crack Growth Model

The fatigue initiation and non-self-similar fatigue crack growth behavior of three notched compact tension and shear specimens of 16MnR steel under mixed mode I/II loading were investigated. The plane-stress finite element model with the implemented Armstrong-Frederick type cyclic plasticity model was used to calculate the elastic-plastic stress-strain responses. A recently developed dynamic crack growth model was used to simulate the effects of loading history on the successive crack growth. With the outputted numerical results, a multiaxial fatigue damage criterion based on the critical plane was used to determine the location of fatigue initiation. A formula of fatigue crack growth rate, which is based on the postulation that the fatigue initiation and crack growth have the same damage mechanism, was then used to calculate the transient crack growth rate and determine the non-self-similar crack growth path. The predicted fatigue initiation position, crack path and crack growth rate are in excellent agreement with the experimental data.

Effects of Mixed Mode Loading Conditions on Fatigue Crack Growth Rate

2019 ◽  
Vol 814 ◽  
pp. 176-181
Author(s):  
Sang Hyun Hong ◽  
Sang Deok Kim ◽  
Jae Hoon Kim
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Mixed Mode ◽  
Mode I ◽  
Pure Mode ◽  
Intensity Factors

The fatigue crack growth rate is the most important factor in predicting the life of a product when applying the damage tolerance design concept. Studies related to pure mode I for structures under fatigue loading have been actively conducted, while not many studies are conducted on the mixed mode. In this study, therefore, mixed mode fatigue crack growth experiments were designed using the Compact-Tension-Shear (CTS) specimens and the loading devices, proposed by Richard. Furthermore, the finite element analysis was used in determining the stress intensity factors of CTS specimen. As the results, the fatigue crack growth rate using the equivalent stress intensity factors proposed by previous researchers was lower than that of pure mode I at the initial stage of crack growth when the load angle increases.

Analysis of Mixed-Mode Fatigue Crack Growth under Stress Redistribution at Crack Tips

2011 ◽  
Vol 148-149 ◽  
pp. 552-555
Author(s):  
Wen Feng Tu ◽  
Zeng Liang Gao ◽  
Zhao Ji Hu
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Mixed Mode ◽  
Growth Parameters ◽  
Stress Redistribution ◽  
Loading Direction ◽  
Crack Tips

The experiments of mixed-mode I-II fatigue crack growth under stress redistribution at crack tips were conducted with compact specimens made of 16MnR steel. This test consisted of the 1st, the 2nd and 3rd step. When the crack reached a certain length in 1st step, the loading direction was switched to a certain angle. Finally, the loading direction was returned to the original orientation. The stress redistribution of mixed-mode fatigue was formed by altering the loading direction at propagating crack tips. A finite element analysis was also conducted to obtain the and values, and then mixed-mode crack growth parameters were adopted to evaluate the crack growth rate and crack paths. The crack growth paths had a tendency perpendicular and across to the loading axis. Right after the loading direction was changed, the crack growth rate was decreased rapidly, and crack growth paths under the stress redistribution zone (SRZ) were affected.

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