scholarly journals Using DIC techniques to measure strain ranges inside the cyclic plastic zone ahead of a fatigue crack tip

2019 ◽  
Vol 13 (49) ◽  
pp. 74-81 ◽  
Author(s):  
Giancarlo Gonzáles ◽  
Julián González ◽  
Jaime Castro ◽  
José Freire
Keyword(s):  
Fatigue Crack ◽  
Plastic Zone ◽  
Crack Tip ◽  
Cyclic Plastic ◽  
Cyclic Plastic Zone

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.

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.

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.

Mapping the cyclic plastic zone to elucidate the mechanisms of crack tip deformation in bulk metallic glasses

2017 ◽  
Vol 110 (8) ◽  
pp. 081903 ◽  
Author(s):  
S. Scudino ◽  
R. N. Shahid ◽  
B. Escher ◽  
M. Stoica ◽  
B. S. Li ◽  
...  
Keyword(s):  
Plastic Zone ◽  
Metallic Glasses ◽  
Bulk Metallic Glasses ◽  
Crack Tip ◽  
Cyclic Plastic ◽  
Cyclic Plastic Zone

A Study on the Cyclic Plastic Zone Size Method, ω*, for Digital Fatigue Life Prediction of Arc-Welded Joints

2003 ◽  
Author(s):  
Tomohiro Hirata ◽  
Toshiaki Nakamaru ◽  
Keisuke Toyama ◽  
Shuichi Magara ◽  
Hiroshi Watanabe ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Plastic Zone ◽  
Welded Joints ◽  
Life Prediction ◽  
Plastic Zone Size ◽  
Fatigue Life Prediction ◽  
Zone Size ◽  
Cyclic Plastic ◽  
Cyclic Plastic Zone
Sign in / Sign up

Export Citation Format

Share Document