Plastic zone at crack tip: A nanolab for formation and study of metallic glassy nanostructures

2009 ◽  
Vol 24 (9) ◽  
pp. 2986-2992 ◽  
Author(s):  
X.X. Xia ◽  
Wei H. Wang ◽  
A. Lindsay Greer
Keyword(s):  
Fracture Surface ◽  
Plastic Zone ◽  
Metallic Glasses ◽  
Room Temperature ◽  
Crack Tip ◽  
Plastic Zone Size ◽  
Fracture Mechanisms ◽  
Clear Correlation ◽  
Zone Size ◽  
Deformation And Fracture

We report that various metallic glassy nanostructures including nanoridges, nanocones, nanowires, nanospheres, and nanoscale-striped patterns are spontaneously formed on the fracture surface of bulk metallic glasses at room temperature. A clear correlation between the dimensions of these nanostructures and the size of the plastic zone at the crack tip has been found, providing a way to control nanostructure sizes by controlling the plastic zone size intrinsically or extrinsically. This approach to forming metallic glassy nanostructures also has implications for understanding the deformation and fracture mechanisms of metallic glasses.

Analytical Prediction Model for Fatigue Crack Propagation Rate under Tension-Compression Loading

2013 ◽  
Vol 842 ◽  
pp. 455-461
Author(s):  
Yu Sha ◽  
Shi Gang Bai ◽  
Ya Hui Wang
Keyword(s):  
Finite Element ◽  
Fatigue Crack ◽  
Plastic Zone ◽  
Crack Propagation ◽  
Compressive Stress ◽  
Fatigue Crack Propagation ◽  
Crack Tip ◽  
Plastic Zone Size ◽  
Zone Size ◽  
Compression Loading

Elastic–plastic finite element analyses have been performed to study the compressive stress effect on fatigue crack growth under applied tension–compression loading. The near crack tip stress, crack tip opening displacement and crack tip plastic zone size were obtained for a kinematic hardening material. The results have shown that the near crack tip local stress, displacement and reverse plastic zone size are controlled by the maximum stress intensity factors Kmax and the applied compressive stress σmaxcom under tension–compression. Based on the finite element analysis results, a fatigue crack propagation model using Kmax and σmaxcom as a parameters under tension–compression loading has been developed.The models under tension–compression loading agreed well with experimental observations.

Micro-cavity Effect on the Plastic Zone Size ahead of the Crack Tip in Confined Plasticity

2010 ◽  
pp. 229-236
Author(s):  
M. El Meguenni ◽  
B. Bachir Bouiadjra ◽  
M. Benguediab ◽  
A. Ziadi ◽  
M. Naït-Abdelaziz ◽  
...  
Keyword(s):  
Plastic Zone ◽  
Crack Tip ◽  
Plastic Zone Size ◽  
Zone Size ◽  
Micro Cavity ◽  
Cavity Effect

207 Simple evaluation method for plastic zone size at a crack tip emanating from notch root

2015 ◽  
Vol 2015.68 (0) ◽  
pp. 53-54
Author(s):  
Shohei MIYANAGA ◽  
Akihide SAIMOTO ◽  
Takuichiro INO ◽  
Shota TANIGAWA ◽  
Takayuki HIGASHI
Keyword(s):  
Plastic Zone ◽  
Evaluation Method ◽  
Notch Root ◽  
Crack Tip ◽  
Plastic Zone Size ◽  
Zone Size ◽  
Simple Evaluation

A Better Estimation of Plastic Zone Size at the Crack Tip Beyond Irwin's Model

2013 ◽  
Vol 80 (5) ◽  
Author(s):  
Y. J. Jia ◽  
M. X. Shi ◽  
Y. Zhao ◽  
B. Liu
Keyword(s):  
Plastic Zone ◽  
Crack Tip ◽  
Plastic Zone Size ◽  
Quantitative Relation ◽  
Small Scale ◽  
Crack Plane ◽  
Zone Size ◽  
Small Scale Yielding ◽  
Scale Yielding ◽  
Remote Stress

Irwin's model on plastic zone at the crack tip is discussed in many fracture mechanics textbooks. However, we found in Irwin's model that the internal resultant force on the crack plane and the one applied in remote field are not strictly balanced. This imbalance leads to the error in the scenario of small scale yielding, and an improper finite plastic zone size (PZS) is predicted when the remote stress approaches the yielding strength. In this paper, an improved model is developed through surrendering some main assumptions used in Irwin's model and an infinite PZS is then predicted as the remote stress goes up close to yielding strength, which implies that this estimation can be applied to situations with large scale yielding. In small scale yielding cases, the new estimation of PZS agrees well with finite element simulation results. In addition, a more accurate quantitative relation between the PZS and the effective stress intensity factor is derived, which might help characterize fracture behaviors in engineering applications.

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