Experimental and numerical investigations on crack propagation characteristics of rock-like specimens with preexisting flaws subjected to combined actions of internal hydraulic pressure and shear force

2021 ◽  
Author(s):  
Weiqiu Kong ◽  
Yong Li ◽  
Lichao Nie ◽  
Zhenxing Dong ◽  
Weibing Cai ◽  
...  
Keyword(s):  
Crack Propagation ◽  
Shear Force ◽  
Hydraulic Pressure ◽  
Propagation Characteristics ◽  
Numerical Investigations ◽  
Combined Actions

Crack propagation and coalescence characteristics of rock-like specimen containing preexisting flaws subjected to internal hydraulic pressure and shear force

2021 ◽  
Author(s):  
Yong Li ◽  
Weiqiu Kong ◽  
Weishen Zhu ◽  
Guannan Wu ◽  
Zhiheng Wang ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Shear Force ◽  
Cement Mortar ◽  
Hydraulic Pressure ◽  
Shear Direction ◽  
Direct Shear ◽  
Horizontal Shear ◽  
Shear Tests ◽  
Direct Shear Tests

<p><strong>Abstract:</strong> Based on laboratory direct shear tests and discrete element theory, the crack propagation and coalescence mechanism and numerical simulation of cement mortar specimens considering the combined actions of internal hydraulic pressure and shear force were carried out. We completed the filling of the internal hydraulic pressure in the cement mortar specimens with preexisting flaws, and performed the direct shear tests on the specimens. In the numerical analysis, the pipe domain model in the two dimensional particle flow code (PFC2D) was modified owing to the high brittleness and low permeability of the cement mortar particles in the numerical model. We also modified the calculation rules of the interaction between the fluid and cement mortar particles, and proposed an improved fluid-solid coupling model which is more suitable for the high brittle cement mortar. Under the action of internal hydraulic pressure, a tensile region existed at the tip of the preexisting flaws of the cement mortar specimen, which can also explain the crack initiation and propagation along the horizontal shear direction during the stage of crack initiation. However, the fissure water pressure was not completely dissipated because of the high brittleness of the cement mortar and the existence of a large number of micro-cracks in the failure area, which finally resulted in a relatively concentrated horizontal compressive stress, and roughly formed a compressive region with a smaller stress along the horizontal shear direction.</p>

scholarly journals Crack Propagation Characteristics and Fracture Surface Energy of Boride Cermets

2002 ◽  
Vol 66 (11) ◽  
pp. 1116-1121
Author(s):  
Hiromoto Kitahara ◽  
Yasuhiro Yoshikawa ◽  
Fuyuki Yoshida ◽  
Hideharu Nakashima ◽  
Kazuo Hamashima ◽  
...  
Keyword(s):  
Fracture Surface ◽  
Surface Energy ◽  
Crack Propagation ◽  
Propagation Characteristics ◽  
Fracture Surface Energy

scholarly journals Investigation on Dynamic Propagation Characteristics of In-Plane Cracks in PVB Laminated Glass Plates

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Xiaoqing Xu ◽  
Bohan Liu ◽  
Yibing Li
Keyword(s):  
Crack Propagation ◽  
Impact Loading ◽  
Crack Tip ◽  
Stress Waves ◽  
Critical Parameters ◽  
Propagation Mechanism ◽  
High Speed Photography ◽  
Laminated Glass ◽  
Propagation Characteristics ◽  
Crack Propagation Mechanism

Polyvinyl butyral (PVB) laminated glass has been widely used as an important component of mechanical and construction materials. Cracks on PVB laminated glass are rich in impact information, which contribute to its impact resistance design. In this paper, a three-dimensional (3D) numerical simulation model describing PVB laminated glass under impact loading is firstly established and validated qualitatively and quantitatively compared with the corresponding experimental results recorded by the high-speed photography system. In the meantime, the extended finite element method (XFEM) is introduced to analyze the crack propagation mechanism of laminated glass based on dynamic stress intensity factors (DSIFs) and propagations of stress waves. Parametric studies are then carried out to investigate the influence of five critical parameters, that is, plate dimension, crack length, impact energy, glass properties, and PVB properties, on crack propagation characteristics of laminated glass. Results show that the interaction between crack tip and stress waves as well as the propagations of stress waves corresponds to the fluctuations of DSIFs at crack tip. Both the structure and material variables are proven to play a very important role in glass cracking DSIFs and thus govern the crack propagation behavior. Results may provide fundamental explanation to the basic crack propagation mechanism on radial cracks in PVB laminated glass under impact loading conditions, thus to instruct its impact design improvement.

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