Effect of hydrogen on dislocation structures around a mixed-mode fatigue crack tip in a single-crystalline iron–silicon alloy

2011 ◽  
Vol 64 (8) ◽  
pp. 721-724 ◽  
Author(s):  
Yoshimasa Takahashi ◽  
Junji Sakamoto ◽  
Masaki Tanaka ◽  
Kenji Higashida ◽  
Hiroshi Noguchi
Keyword(s):  
Fatigue Crack ◽  
Mixed Mode ◽  
Crack Tip ◽  
Single Crystalline ◽  
Silicon Alloy ◽  
Iron Silicon

Characterization of dislocation structures around a mixed-mode fatigue crack tip in a single-crystalline iron–silicon alloy

2011 ◽  
Vol 64 (2) ◽  
pp. 157-160 ◽  
Author(s):  
Yoshimasa Takahashi ◽  
Junji Sakamoto ◽  
Masaki Tanaka ◽  
Kenji Higashida ◽  
Hiroshi Noguchi
Keyword(s):  
Fatigue Crack ◽  
Mixed Mode ◽  
Crack Tip ◽  
Single Crystalline ◽  
Silicon Alloy ◽  
Iron Silicon

scholarly journals TEM Observation of Cyclic Deformation around an Oblique Fatigue Crack Tip in Single-crystalline Fe-3.2wt.%Si Alloy

2010 ◽  
Vol 76 (762) ◽  
pp. 251-253 ◽  
Author(s):  
Yoshimasa TAKAHASHI ◽  
Junji SAKAMOTO ◽  
Masaki TANAKA ◽  
Kenji HIGASHIDA ◽  
Hiroshi NOGUCHI
Keyword(s):  
Fatigue Crack ◽  
Cyclic Deformation ◽  
Crack Tip ◽  
Single Crystalline

scholarly journals Identification and Prediction of Mixed-Mode Fatigue Crack Path in High Strength Low Alloy Steel

Proceedings ◽  
2018 ◽  
Vol 2 (8) ◽  
pp. 504
Author(s):  
Jie Zhang ◽  
Cedric Kiekens ◽  
Stijn Hertelé ◽  
Wim De Waele
Keyword(s):  
Fatigue Crack ◽  
Digital Image Correlation ◽  
Crack Propagation ◽  
Digital Image ◽  
Mixed Mode ◽  
Standardized Test ◽  
Crack Tip ◽  
Shear Loading ◽  
Image Correlation ◽  
Crack Trajectory

The trajectory of fatigue crack growth is influenced by many parameters and can be irregular due to changes in stress distribution or in material properties as the crack progresses. Images of the surface of a standardized test specimen can be used to visualize the crack trajectory in a non-destructive way. Accurately identifying the location of the crack tip, however, is challenging and requires devoted image postprocessing. In this respect, digital image correlation allows to obtain full field displacement and strain fields by analysing changes of digital images of the same sample at different stages of loading. This information can be used for the purpose of crack tip tracking. This paper presents a combined experimental-numerical study of detection and prediction of fatigue crack propagation path by means of digital image correlation (DIC) and the extended finite element method (X-FEM). Experimental validation and analyses are carried out on a modified C(T) specimen in which a curved crack trajectory is triggered by introducing mixed-mode (tension + shear) loading. The developed tools are used for validating an automated framework for crack propagation prediction.

On the micromechanism of hydrogen-assisted cracking in a single-crystalline iron–silicon alloy thin sheet

2011 ◽  
Vol 64 (6) ◽  
pp. 537-540 ◽  
Author(s):  
Yoshimasa Takahashi ◽  
Keigo Yamaguchi ◽  
Masaki Tanaka ◽  
Kenji Higashida ◽  
Hiroshi Noguchi
Keyword(s):  
Thin Sheet ◽  
Single Crystalline ◽  
Silicon Alloy ◽  
Iron Silicon ◽  
Hydrogen Assisted Cracking

The Characteristics of Propagation for Mixed-Mode Fatigue Crack under Stress Re-Distribution at Fatigue Crack Tip

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1922-1927 ◽  
Author(s):  
Sam Hong Song ◽  
Jeong Moo Lee
Keyword(s):  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Mixed Mode ◽  
Applied Load ◽  
Crack Tip ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Stress Redistribution ◽  
Fatigue Crack Propagation Rate

The practical condition of applied load represents mixed-mode loading condition due to complications of element geometry and applied load. Also, the characteristics of fatigue crack propagation under mixed mode were affected by constrained shape of structures and applied load variation. There are continuous variations of stress condition at crack tip on the fatigue crack during propagation. Therefore, it is necessary to investigate the propagation behavior of mixed-mode fatigue crack under stress redistribution condition. We established the experimental method in order to form the stress redistribution condition. It is assumed that the stress around the crack tip under mixed-mode fatigue loading is redistributed. This test consisted of the 1st and the 2nd round of tests. The stress re distribution was formed by changing the loading direction at propagating mixed-mode fatigue crack tip. In this study, the behavior of mixed-mode fatigue crack affected by stress redistribution was investigated by comparing fatigue crack propagation rate, fatigue crack propagation paths and fatigue crack branch angle. From the experiment, as loading application angle and thickness change, the fatigue crack propagation rate and angle under mixed mode were affected by stress redistribution.

scholarly journals TEM Analysis on the Effect of Hydrogen on Cyclic Deformation around an Oblique Fatigue Crack Tip in Single-Crystalline Fe-3.2wt.%Si Alloy

2010 ◽  
Vol 76 (767) ◽  
pp. 1002-1004
Author(s):  
Yoshimasa TAKAHASHI ◽  
Junji SAKAMOTO ◽  
Masaki TANAKA ◽  
Kenji HIGASHIDA ◽  
Hiroshi NOGUCHI
Keyword(s):  
Fatigue Crack ◽  
Cyclic Deformation ◽  
Crack Tip ◽  
Tem Analysis ◽  
Single Crystalline

scholarly journals Experimental and theoretical analysis of heat flux at fatigue crack tip under mixed mode loading

2019 ◽  
Vol 18 ◽  
pp. 608-615
Author(s):  
A. Vshivkov ◽  
A. Iziumova ◽  
R. Yarullin ◽  
V. Shlyannikov ◽  
O. Plekhov
Keyword(s):  
Heat Flux ◽  
Fatigue Crack ◽  
Theoretical Analysis ◽  
Mixed Mode ◽  
Crack Tip ◽  
Mixed Mode Loading

Cyclic Plasticity of a Cracked Structure Subjected to Mixed Mode Loading

2007 ◽  
Vol 348-349 ◽  
pp. 105-108 ◽  
Author(s):  
Sylvie Pommier
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Mixed Mode ◽  
Crack Tip ◽  
Cyclic Plasticity ◽  
Loading Conditions ◽  
Mixed Mode Loading ◽  
Crack Tip Plasticity

Cyclic plasticity in the crack tip region is at the origin of various history effects in fatigue. For instance, fatigue crack growth in mode I is delayed after the application of an overload because of the existence of compressive residual stresses in the overload’s plastic zone. Moreover, if the overload’s ratio is large enough, the crack may grow under mixed mode condition until it has gone round the overload’s plastic zone. Thus, crack tip plasticity modifies both the kinetics and the crack’s plane. Therefore modeling the growth of a fatigue crack under complex loading conditions requires considering the effects of crack tip plasticity. Finite element analyses are useful for analyzing crack tip plasticity under various loading conditions. However, the simulation of mixed mode fatigue crack growth by elastic-plastic finite element computations leads to huge computation costs, in particular if the crack doesn’t remain planer. Therefore, in this paper, the finite element method is employed only to build a global constitutive model for crack tip plasticity under mixed mode loading conditions. Then this model can be employed, independently of any FE computation, in a mixed mode fatigue crack growth criterion including memory effects inherited from crack tip plasticity. This model is developed within the framework of the thermodynamics of dissipative processes and includes internal variables that allow modeling the effect of internal stresses and to account for memory effects. The model was developed initially for pure mode I conditions. It was identified and validated for a 0.48%C carbon steel. It was shown that the model allows modeling fatigue crack growth under various variable amplitude loading conditions [1]. The present paper aims at showing that a similar approach can be applied for mixed mode loading conditions so as to model, finally, mixed mode fatigue crack growth.

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