scholarly journals On the Application of PDS-FEM for Simulating 3D Wing Crack Growth in Brittle Elastic Solids

2013 ◽  
Vol 69 (2) ◽  
pp. I_125-I_132
Author(s):  
MADDEGEDARA Lalith ◽  
Muneo HORI ◽  
Hide SAKAGUCHI ◽  
Tsuyoshi ICHIMURA
Keyword(s):  
Crack Growth ◽  
Elastic Solids ◽  
Wing Crack ◽  
3D Wing

Application of PDS-FEM for Simulating 3D Wing Crack Growth

2014 ◽  
Vol 553 ◽  
pp. 725-730 ◽  
Author(s):  
M.L.L. Wijerathne ◽  
Muneo Hori ◽  
T. Okinaka ◽  
Hide Sakaguchi
Keyword(s):  
Crack Growth ◽  
Large Scale ◽  
Shape Functions ◽  
Mode Iii ◽  
Elastic Solids ◽  
Wing Crack ◽  
Linear Elastic ◽  
Failure Treatment ◽  
Scale Models ◽  
3D Wing

3D wing crack growth is not a well understood phenomenon, although it is one of the key mechanisms of the failure of brittle materials under compression. Using PDS-FEM, we simulated the growth of 3D wing cracks emerging from pre-existing cracks in blocks of brittle linear elastic solids, under compression. The complex 3D wing crack profiles are reproduced with PDS-FEM, which uses non-overlapping shape functions of conjugate geometries to approximate functions and their derivatives. PDS-FEM provides numerically efficient failure treatment for modeling 3D cracks, making use of the numerous discontinuities in the approximated displacement field. Large scale models with several million elements are used to reproduce the experimentally observed details of wing crack profiles. The bending of crack surfaces at the tip of mode-I regions, extension of wing cracks and the growth of tensile openings or petal cracks at mode-III regions are reproduced, demonstrating the applicability of PDS-FEM for studying 3D wing crack growth phenomena.

Anti-Wing Crack Growth from Surface Flaw in Real Rock under Uniaxial Compression

2008 ◽  
pp. 825-826 ◽  
Author(s):  
Robina H. C. Wong ◽  
Y. S. H. Guo ◽  
L. Y. Li ◽  
K. T. Chau ◽  
W. S. Zhu ◽  
...  
Keyword(s):  
Crack Growth ◽  
Uniaxial Compression ◽  
Surface Flaw ◽  
Wing Crack

Crack Growth Mechanisms from 3-D Surface Flaw with Varied Dipping Angle under Uniaxial Compression

2007 ◽  
Vol 353-358 ◽  
pp. 2353-2356 ◽  
Author(s):  
Y.S.H. Guo ◽  
R.H.C. Wong ◽  
K.T. Chau ◽  
Wei Shen Zhu ◽  
Shu Cai Li
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Crack Growth ◽  
Uniaxial Compression ◽  
Axial Loading ◽  
Growth Direction ◽  
Surface Flaw ◽  
Growth Mechanisms ◽  
Wing Crack ◽  
Ae Energy

A number of instability problems in rock engineering projects are caused by crack propagation. However, crack growth mechanisms from 3-dimentional flaw are not fully understood, in particular for 3-D flaw case with varied dipping angle. This study focuses on 3-D surface flaw using real rock specimens containing a flaw with varied inclination angle α from axial loading and dipping angle γ from specimen surface under uniaxial compression. Acoustic emission technique was used for tracing the initiation and growth of micro-cracks inside of specimen. It was found that crack growth process is affected by the dipping angle γ of the 3-D flaw. When dipping angle γ ≠ 90º, the thickness of rock above the flaw plane is thinner than that of below the flaw plane. As a result, compressive crack and wing crack initiated easily from the thinner flaw tips. And, the normalized stress for crack initiation σi /σc, AE events and the AE energy for crack growth decreases with the dipping angle γ. However, for γ = 90º, the thickness of rock above and below of the flaw tips is the same, it was observed that anti-wing crack (crack growth direction opposite to wing crack) initiated first at a certain place away from the flaw tips, then wing crack and compressive crack emerged at the late stage. For this case, the stress σi /σc, AE events and the AE energy for crack initiation and propagation are at a high value. Thus, for rock mass contains flaws geometry with small dipping angle, some problems of crack propagation may be induced easily during excavation.

The Crack Growth Mechanism from 3-D Surface Flaw with Strain and Acoustic Emission Measurement under Axial Compression

2007 ◽  
Vol 353-358 ◽  
pp. 2357-2360 ◽  
Author(s):  
R.H.C. Wong ◽  
Y.S.H. Guo ◽  
K.T. Chau ◽  
Wei Shen Zhu ◽  
Shu Cai Li
Keyword(s):  
Acoustic Emission ◽  
Energy Release ◽  
Crack Growth ◽  
Growth Mechanism ◽  
Surface Flaw ◽  
Emission Measurement ◽  
Wing Crack ◽  
Crack Patterns ◽  
Useful Knowledge ◽  
Crack Growth Mechanism

This paper presents the crack growth mechanism from a 3-D surface flaw on gabbro specimens using strain measurement and acoustic emission (AE) technique. Based on the results of strain and AE measurement, microcracks initiated inside the rock and extend to the surface of the specimen. With the observation from the measurements, four types of crack patterns initiate wing crack, anti-wing crack (opposite direction of wing crack), petal crack and compressive crack. The strain values of anti-wing cracks are larger 1 to 2 times than that of wing crack. The AE energy release from anti-wing crack is higher 2.5 times than that of wing crack, while the energy release form wing crack is the least but the compressive crack is the highest. Thus, the appearance of initiation and propagation of the anti-wing crack and compressive crack are very actively than that of the wing crack. The strain and AE measurement is not only to provide a clear concept on the mechanisms of crack growth form a 3-D surface flaw but also to provide useful knowledge on the AE property of the crack patterns.

The Wing Crack Growth Processes of Rock Induced by Hydraulic Pressure

2013 ◽  
Vol 405-408 ◽  
pp. 611-616
Author(s):  
Shi Bin Tang ◽  
Zheng Zhao Liang ◽  
Hong Li ◽  
Chu Nan Tang
Keyword(s):  
Fluid Flow ◽  
Crack Growth ◽  
Hydraulic Pressure ◽  
Flow Properties ◽  
Wing Crack ◽  
Growth Processes ◽  
Mechanical Coupling ◽  
Crack Tips ◽  
Crack Growth Mechanism ◽  
Crack Growth Path

The pre-existing fractures in rock can close, open and growth as it subjected to mechanical or environment loading, which can in turn change the structure of the rock and alter its fluid flow properties. In order to study the crack growth processes of pre-existing fracture in rock under the condition of hydraulic and mechanical coupling, a numerical tool, named F-RFPA2D which takes into account the growth of existing fractures and the formation of new fractures, is used for this purpose. By considering the effect of hydraulic pressure filling into the wing crack, the behavior of fluid flow, damage evolution and their coupling action in the pre-existing and the newly formed fractures are studied in detail. The modeling results suggest that the hydraulic pressure in the crack enhanced the tensile stresses at the crack tips, resulting in crack growth path is different from that without hydraulic pressure loading. The wing crack growth mechanism under the coupling of hydraulic and mechanical is discussed, which provides a good reference for studying on the hydraulic fracturing in rock masses.

Influence of Free Boundary on A Behavior of Wing Crack Growth

2002 ◽  
Vol 2002.2 (0) ◽  
pp. 185-186
Author(s):  
Akihide SAIMOTO ◽  
Yasufumi IMAI
Keyword(s):  
Free Boundary ◽  
Crack Growth ◽  
Wing Crack
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