Fatigue crack growth determination based on cyclic plastic zone and cyclic J‐integral in kinematic–isotropic hardening materials with considering Chaboche model

2020 ◽  
Vol 43 (11) ◽  
pp. 2668-2682
Author(s):  
Reza Hosseini ◽  
Rahman Seifi
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Plastic Zone ◽  
Crack Growth ◽  
Isotropic Hardening ◽  
J Integral ◽  
Cyclic Plastic ◽  
Cyclic Plastic Zone ◽  
Chaboche Model

A Model of Fatigue Crack Growth Based on Damage Accumulation

2004 ◽  
Author(s):  
Satish Chand ◽  
K. N. Pandey
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Plastic Zone ◽  
Crack Growth ◽  
Damage Accumulation ◽  
Process Zone ◽  
Crack Tip ◽  
Cyclic Plastic ◽  
Cyclic Plastic Zone ◽  
Material Element

A fatigue crack growth model based on cumulative damage is presented, when a material element ahead of the crack tip, is approached by the tip of the crack. The cyclic plastic zone and process zone ahead of the crack tip are taken as the area where damage accumulation takes place when the material element, first, enters into the cyclic plastic zone and then into the process zone. During this period, the Coffin-Manson damage law in conjunction with Miner’s linear damage accumulation is used to determine the damage in the material element. A constant strain gradient was assumed along the process zone ahead of the crack tip and the size of process zone was taken to be variable and dependent on the range of stress intensity factor. For a cyclic loading, the effective crack driving force takes into consideration the crack tip blunting process. The model results are in good agreement with experimental data available in literature for a number of materials.

Modeling of Fatigue Crack Growth under High-Low Sequence Loading

2012 ◽  
Vol 224 ◽  
pp. 65-68
Author(s):  
Zhi Wei Yao ◽  
Bao Xiang Qiu ◽  
Xiao Gui Wang
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Plastic Zone ◽  
Crack Growth ◽  
Crack Closure ◽  
Fatigue Crack Growth Rate ◽  
Cyclic Plastic ◽  
Cyclic Plastic Zone

The fatigue crack growth behavior of one compact tension specimen of 16MnR steel under high-low sequence loading was investigated. The symmetric half finite element model under plane-stress state was used to calculate the elastic-plastic stress-strain responses, in which the Armstrong-Frederick type cyclic plasticity model was implemented as a user material subroutine UMAT of ABAQUS. A recently developed dynamic crack growth model was used to simulate the effects of high loading step on the successive low loading step. The detailed evolution process of the crack closure and cyclic plastic zone within the retardation region of fatigue crack growth was obtained. The extend of the crack closure, the size of cyclic plastic zone and the stress gradient have significant influence on the fatigue crack growth rate. The predicted fatigue crack growth rate is in good agreement with the experimental data.

scholarly journals Advantageous Description of Short Fatigue Crack Growth Rates in Austenitic Stainless Steels with Distinct Properties

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 475
Author(s):  
Lukáš Trávníček ◽  
Ivo Kuběna ◽  
Veronika Mazánová ◽  
Tomáš Vojtek ◽  
Jaroslav Polák ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Stainless Steels ◽  
Growth Rates ◽  
Large Scale ◽  
J Integral ◽  
Scale Yielding ◽  
Residual Fatigue ◽  
Crack Growth Rates

In this work two approaches to the description of short fatigue crack growth rate under large-scale yielding condition were comprehensively tested: (i) plastic component of the J-integral and (ii) Polák model of crack propagation. The ability to predict residual fatigue life of bodies with short initial cracks was studied for stainless steels Sanicro 25 and 304L. Despite their coarse microstructure and very different cyclic stress–strain response, the employed continuum mechanics models were found to give satisfactory results. Finite element modeling was used to determine the J-integrals and to simulate the evolution of crack front shapes, which corresponded to the real cracks observed on the fracture surfaces of the specimens. Residual fatigue lives estimated by these models were in good agreement with the number of cycles to failure of individual test specimens strained at various total strain amplitudes. Moreover, the crack growth rates of both investigated materials fell onto the same curve that was previously obtained for other steels with different properties. Such a “master curve” was achieved using the plastic part of J-integral and it has the potential of being an advantageous tool to model the fatigue crack propagation under large-scale yielding regime without a need of any additional experimental data.

The effect of crystal orientations on fatigue crack growth

1968 ◽  
Vol 46 (19) ◽  
pp. 2225-2226 ◽  
Author(s):  
R. W. Lardner
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Plastic Zone ◽  
Crack Growth ◽  
Average Rate ◽  
Previous Theory ◽  
Line Material ◽  
Dislocation Arrays ◽  
Mode 2 ◽  
Slip Planes

A previous theory of fatigue crack growth in metals was based on an analysis of the plastic zone at the tip of a crack in terms of coplanar dislocation arrays. This analysis has been extended to the case of oblique slip planes. It is shown that, for the case of a crack growing in mode 2 through a polycrystal-line material, the average rate of growth through the differing orientations of many grains is almost identical with that obtained by the coplanar analysis.

scholarly journals Short fatigue crack growth in welded joints described by the effective cyclic J-integral

2018 ◽  
Vol 165 ◽  
pp. 09002
Author(s):  
Désiré Tchoffo Ngoula ◽  
Michael Vormwald
Keyword(s):  
Fatigue Crack ◽  
Fatigue Life ◽  
Fatigue Crack Growth ◽  
Residual Stresses ◽  
Crack Growth ◽  
Welded Joints ◽  
Driving Force ◽  
J Integral ◽  
Crack Driving Force ◽  
Short Fatigue Crack

The purpose of the present contribution is to predict the fatigue life of welded joints by using the effective cyclic J-integral as crack driving force. The plasticity induced crack closure effects and the effects of welding residual stresses are taken into consideration. Here, the fatigue life is regarded as period of short fatigue crack growth. The node release technique is used to perform finite element based crack growth analyses. For fatigue lives calculations, the effective cyclic J-integral is employed in a relation similar to the Paris (crack growth) equation. For this purpose, a specific code was written for the determination of the effective cyclic J-integral for various lifetime relevant crack lengths. The effects of welding residual stresses on the crack driving force and the calculated fatigue lives are investigated. Results reveal that the influence of residual stresses can be neglected only for large load amplitudes. Finally, the predicted fatigue lives are compared with experimental data: a good accordance between both results is achieved.

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