scholarly journals Plastic Strain Distribution at Fatigue Crack Tip in Aluminum

1974 ◽  
Vol 23 (244) ◽  
pp. 64-68
Author(s):  
Shigeru KITAGAWA
Keyword(s):  
Fatigue Crack ◽  
Plastic Strain ◽  
Strain Distribution ◽  
Crack Tip ◽  
Plastic Strain Distribution

Plastic Strain Distribution at the Tips of Propagating Fatigue Cracks

1976 ◽  
Vol 98 (1) ◽  
pp. 24-29 ◽  
Author(s):  
D. L. Davidson ◽  
J. Lankford
Keyword(s):  
Aluminum Alloy ◽  
Fatigue Crack ◽  
Plastic Strain ◽  
Plastic Zone ◽  
Strain Distribution ◽  
Dimensionless Parameter ◽  
Fatigue Cracks ◽  
Crack Tip ◽  
Cyclic Plastic Zone ◽  
Plastic Zones

The techniques of selected area electron channeling and positive replica examination have been used to study the plastic zones attending fatigue crack propagation in 304 SS, 6061-T6 aluminum alloy, and Fe-3Si steel. These observations allowed the strain distribution at the crack tip to be determined. The results indicate that the concepts of a monotonic and a cyclic plastic zone are essentially correct, with the strains at demarcation between these two zones being 3 to 6 percent. Strain distribution varies as r−1/2 in the cyclic zone and as ln r in the monotonic plastic zone. The strain distributions for all materials studied may be made approximately coincident by using a dimensionless parameter related to distance from the crack tip.

scholarly journals Quantitative measurement of plastic strain field at a fatigue crack tip

2012 ◽  
Vol 468 (2144) ◽  
pp. 2399-2415 ◽  
Author(s):  
Y. Yang ◽  
M. Crimp ◽  
R. A. Tomlinson ◽  
E. A. Patterson
Keyword(s):  
Fatigue Crack ◽  
Plastic Strain ◽  
Plastic Zone ◽  
Strain Distribution ◽  
Pure Titanium ◽  
Crack Tip ◽  
Plastic Zone Size ◽  
Uniaxial Tensile ◽  
Commercially Pure Titanium ◽  
Zone Size

A novel approach is introduced to map the mesoscale plastic strain distribution resulting from heterogeneous plastic deformation in complex loading and component geometries, by applying the discrete Fourier transform (DFT) to backscattered electron (BSE) images of polycrystalline patches. These DFTs are then calibrated against the full width at half the maximum of the central peak of the DFTs collected from the same material tested under in situ scanning electron microscopy uniaxial tensile conditions, which indicates a close relationship with the global tensile strain. In this work, the technique is demonstrated by measuring the residual strain distribution and plastic zone size around a fatigue crack tip in a commercially pure titanium compact tension specimen, by collecting BSE images in a 15×15 array of 115 μm square images around the fatigue crack tip. The measurement results show good agreement with the plastic zone size and shape measured using thermoelastic stress analysis.

scholarly journals Study on the Influence of the Gurson–Tvergaard–Needleman Damage Model on the Fatigue Crack Growth Rate

Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1183
Author(s):  
Edmundo R. Sérgio ◽  
Fernando V. Antunes ◽  
Diogo M. Neto ◽  
Micael F. Borges
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Plastic Strain ◽  
Crack Growth ◽  
Damage Model ◽  
Crack Tip ◽  
Strength Parameter ◽  
Stress Intensity Factor Range

The fatigue crack growth (FCG) process is usually accessed through the stress intensity factor range, ΔK, which has some limitations. The cumulative plastic strain at the crack tip has provided results in good agreement with the experimental observations. Also, it allows understanding the crack tip phenomena leading to FCG. Plastic deformation inevitably leads to micro-porosity occurrence and damage accumulation, which can be evaluated with a damage model, such as Gurson–Tvergaard–Needleman (GTN). This study aims to access the influence of the GTN parameters, related to growth and nucleation of micro-voids, on the predicted crack growth rate. The results show the connection between the porosity values and the crack closure level. Although the effect of the porosity on the plastic strain, the predicted effect of the initial porosity on the predicted crack growth rate is small. The sensitivity analysis identified the nucleation amplitude and Tvergaard’s loss of strength parameter as the main factors, whose variation leads to larger changes in the crack growth rate.

Local Texture Evolution by Rate-Independent Polycrystal Model Allowing for Coordination of Interacting Crystals

2005 ◽  
Vol 495-497 ◽  
pp. 965-970
Author(s):  
A.A. Zisman ◽  
Nikolay Y. Zolotorevsky ◽  
N.Yu. Ermakova
Keyword(s):  
Experimental Data ◽  
Plastic Strain ◽  
Strain Distribution ◽  
Texture Evolution ◽  
Spatial Coordination ◽  
Local Texture ◽  
Plastic Strain Distribution ◽  
Simulation Results

A rate-independent polycrystal model, allowing for the shape and spatial coordination of neighboring constitutive crystals and for the plastic strain distribution among them, has been used to simulate the local texture evolution in an Al polycrystal under compression. The simulation results compare favourably to relevant experimental data and show the reorientation path of each crystal to strongly depend on orientations of its immediate neighbors.

scholarly journals Visualization of Plastic Strain Distribution in a Dual-Phase Steel Using High-Precision Grid-Markers

2012 ◽  
Vol 98 ◽  
pp. 303-310 ◽  
Author(s):  
Hidekazu Minami ◽  
Hiroshi Ikeda ◽  
Tatsuya Morikawa ◽  
Kenji Higashida ◽  
Tsuyoshi Mayama ◽  
...  
Keyword(s):  
Plastic Strain ◽  
High Precision ◽  
Strain Distribution ◽  
Dual Phase Steel ◽  
Dual Phase ◽  
Plastic Strain Distribution
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