Two-dimensional characterization of crack initiation and propagation during hydraulic fracturing in brittle materials

2019 ◽  
Author(s):  
Farzin Hamidi
Keyword(s):  
Crack Initiation ◽  
Hydraulic Fracturing ◽  
Brittle Materials ◽  
Two Dimensional ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation

scholarly journals Characterization of the crack initiation and propagation in Alloy 600 with a cold-worked surface

2019 ◽  
Vol 152 ◽  
pp. 82-92 ◽  
Author(s):  
Zhao Shen ◽  
Kai Chen ◽  
David Tweddle ◽  
Guanze He ◽  
Koji Arioka ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Alloy 600 ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation ◽  
Cold Worked

Analysis of Shear Stress of Two Elasto-Plastic Random Surfaces

2011 ◽  
Vol 279 ◽  
pp. 224-229
Author(s):  
Lian Feng Lai ◽  
Cheng Hui Gao ◽  
Jian Meng Huang
Keyword(s):  
Shear Stress ◽  
Crack Initiation ◽  
Surface Crack ◽  
Wear Mechanisms ◽  
Shear Stresses ◽  
Two Dimensional ◽  
Crack Initiation And Propagation ◽  
Fea Model ◽  
Initiation And Propagation ◽  
Surface Crack Initiation

A FEA model of two-dimensional (2D) sliding between two interfering fractal rough solids was build, and the results was presented. The trends in shear stress between the rough solids were provided by the FEA. Combined with the delaminating theory of wear, the Maximum shear stresses and its distance are presented when loading and sliding. The result showed that the Maximum shear stresses was located in the subsurface which range about 2 to 8 um from the surface. In addition, with different plastic characteristics, the location of Maximum shear stresses were different. With modeling the contact and sliding between rough surfaces, the friction, sub-surface crack initiation and propagation and wear mechanisms can be understood deeply.

scholarly journals Mechanisms of Crack Initiation and Propagation in Dense Linear Multihole Directional Hydraulic Fracturing

2019 ◽  
Vol 2019 ◽  
pp. 1-15
Author(s):  
Jiangwei Liu ◽  
Changyou Liu ◽  
Qiangling Yao
Keyword(s):  
Rock Mass ◽  
Crack Initiation ◽  
Hydraulic Fracturing ◽  
Principal Stress ◽  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation ◽  
Coal Rock

Artificially fracturing coal-rock mass serves to form break lines therein, which is related to the distribution of cracked boreholes. For this reason, we use physical experiments and numerical simulations to study the crack initiation and propagation characteristics of dense linear multihole drilling of fractured coal-rock mass. The results indicate that only in the area between the first and last boreholes can hydraulic fracturing be controlled by dense linear multihole expansion along the direction of the borehole line; in addition, no directional fracturing occurs outside the drilling section. Upon increasing parameters such as the included angle θ between the drilling arrangement line and the maximum principal stress σ1 direction, the drilling spacing D, the difference Δσ in principal stress, etc., the effect of directional fracture is gradually weakened, and the hydraulic fractures reveal three typical cracking modes: cracking along the borehole line, bidirectional cracking (along the borehole line and perpendicular to the minimum principal stress σ3), and cracking perpendicular to σ3. Five propagation modes also appear in sequence: propagating along borehole line, step-like propagation, S-shaped propagation, bidirectional propagation (along the borehole line and perpendicular to σ3), and propagation perpendicular to σ3. Based on these results, we report the typical characteristics of three-dimensional crack propagation and discuss the influence of the gradient of pore water pressure. The results show clearly that crack initiation and propagation are affected by both the geostress field and the pore water pressure. The pore water pressure will exhibit a circular-local contact-to-integral process during crack initiation and expansion. When multiple cracks approach, the superposition of pore water pressure at the tip of the two cracks increases the damage to the coal rock, which causes crack reorientation and intersection.

Crack initiation and propagation in a post-and-core restored maxillary first premolar: A two-dimensional analysis

2019 ◽  
Vol 4 (2) ◽  
pp. 39-44
Author(s):  
Veronika Fedotova ◽  
Estevam Barbosa de Las Casas ◽  
Osvaldo L. Manzoli ◽  
Claudia M.A. Mattos ◽  
Eduardo A. Rodrigues
Keyword(s):  
Crack Initiation ◽  
Dimensional Analysis ◽  
Two Dimensional ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation ◽  
Post And Core
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