Study on the static critical stress intensity factors of sandstone in a water environment based on semicircular bending specimens

2021 ◽  
Vol 116 ◽  
pp. 103106
Author(s):  
Shibin Tang ◽  
Jiaming Li ◽  
Leitao Zhang ◽  
Zhaosheng Liu ◽  
Shaoquan Wang ◽  
...  
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Critical Stress ◽  
Water Environment ◽  
Intensity Factors ◽  
Semicircular Bending

scholarly journals Compression and Shear Fracture Analysis of Boundary Cracks Containing Water in Rock

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhensheng Yang ◽  
Fulin Li ◽  
Tianran Ma
Keyword(s):  
Stress Intensity ◽  
Friction Coefficient ◽  
Stress Intensity Factors ◽  
Underground Mining ◽  
Shear Fracture ◽  
Water Environment ◽  
Initial Crack ◽  
Open Boundary ◽  
Shear Stresses ◽  
Intensity Factors

In order to conserve the water resource during underground mining, the fracture and mechanical properties of rock are important for the stability of water-resisting layers, especially for the fracture behavior of boundary cracks containing water in rock. Considering the swelling of rock under water environment and the influence of water on rock, the stress intensity factors of modes I and II are derived for boundary cracks in rock under compressive and shear stresses. The cracks are divided into the closed and open states. The effects of the crack inclination angle, friction coefficient between crack surfaces, and initial crack length on stress intensity factors are also taken into account. The stress intensity factors for closed and open boundary cracks are verified by numerical and physical experiments, respectively, and the deviation of the results is within 5%. It is shown that pore pressure has different effects on the relationship between stress intensity factor and friction coefficient under different lateral pressures. The effect of water on crack propagation is mainly due to the deterioration of the fracture toughness of the rock. It is found that the critical coefficient λc is a key parameter to determine whether the boundary crack propagates in rock under compression-shear stress. Further studies should be performed to apply the present fracture theory to rock mass or water-resisting layers.

Simple estimation of critical stress intensity factors of wood by tests with double cantilever beam and three-point end-notched flexure

Holzforschung ◽  
2007 ◽  
Vol 61 (2) ◽  
pp. 182-189 ◽  
Author(s):  
Hiroshi Yoshihara
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Cantilever Beam ◽  
Stress Intensity Factors ◽  
Critical Stress ◽  
Double Cantilever Beam ◽  
Western Hemlock ◽  
Mode I ◽  
Intensity Factors

Abstract Simple equations are proposed for calculation of critical stress intensity factors by tests using double cantilever beam (DCB) and three-point end-notched flexure (3ENF). The calculation modes are named here as modes I and II and are based on the beam theory and 95 previously published data on the elasticity properties of woods. The validity of the data was examined on specimens of western hemlock wood with various crack lengths. The influence of the elastic properties is more significant on the stress intensity factor calculated in mode I than that calculated in mode II. Further work is needed, particularly for measuring the mode I stress intensity factor. However, it is obvious from the experiments with western hemlock that the critical stress intensity factors can be determined by the equations proposed here.

Critical stress intensity factors in steel cracked wires

2011 ◽  
Vol 32 (8-9) ◽  
pp. 4424-4429 ◽  
Author(s):  
J. Toribio ◽  
F.J. Ayaso ◽  
B. González ◽  
J.C. Matos ◽  
D. Vergara ◽  
...  
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Critical Stress ◽  
Intensity Factors

Fracture Resistance of Bended Glued Timber Elements with Flaws

2014 ◽  
Vol 988 ◽  
pp. 363-366 ◽  
Author(s):  
Leonid Stupishin ◽  
Victor Kabanov ◽  
Aleksander Masalov
Keyword(s):  
Stress Intensity ◽  
Moisture Content ◽  
Stress Intensity Factors ◽  
Critical Stress ◽  
Critical Stress Intensity Factor ◽  
Intensity Factors ◽  
Front Width ◽  
Glue Joint ◽  
Glued Laminated Timber ◽  
Second Fracture

The test results for deriving of the dependencies of critical stress intensity factors on significant agents are presented for glued laminated timber. The dependencies of critical stress intensity factors on moisture content, width of cross section for I and II forms of fracture are investigated. For the second fracture form the influence of glue joint thickness within the limits of 0.07 - 0.35 mm was estimated. The influence on critical stress intensity factor was estimated also for the moisture content of wood within the limits of 12-35%, for crack front width within the limits of 30 - 140 mm, for loading velocity within the limits of 16 - 32 kN/min, for the form of crack tip, and the location of crack - in glue joint or in wood.

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