A Further Improved Maximum Tangential Stress Criterion for Assessing Mode I Fracture of Rocks Considering Non-singular Stress Terms of the Williams Expansion

2018 ◽  
Vol 51 (11) ◽  
pp. 3471-3488 ◽  
Author(s):  
Ming-Dong Wei ◽  
Feng Dai ◽  
Jia-Wen Zhou ◽  
Yi Liu ◽  
Jing Luo
Keyword(s):  
Tangential Stress ◽  
Maximum Tangential Stress ◽  
Mode I ◽  
Singular Stress ◽  
Mode I Fracture ◽  
Stress Criterion ◽  
Maximum Tangential Stress Criterion

Crack onset assessment near the sharp material inclusion tip by means of modified maximum tangential stress criterion

2017 ◽  
Author(s):  
Ondej Krepl ◽  
Jan Klusák
Keyword(s):  
Stress Concentration ◽  
Crack Initiation ◽  
Tangential Stress ◽  
Maximum Tangential Stress ◽  
Reinforced Composites ◽  
Singular Stress ◽  
Stress Criterion ◽  
Maximum Tangential Stress Criterion ◽  
Particle Reinforced Composites ◽  
Material Discontinuities

In the case of particle reinforced composites, where the particles are in a form of sharp material inclusions, singular stress concentration exists on each tip of each inclusion. This is due to the geometric and material discontinuities between matrix and particle. These points of stress concentration are susceptible of crack initiation and thus often responsible for failure of the whole structure. The modified maximum tangential stress criterion is employed in order to predict crack onset conditions.

Evaluation of size effect on mixed-mode fracture behavior of epoxy/silica nanocomposites

2017 ◽  
Vol 52 (4) ◽  
pp. 239-248 ◽  
Author(s):  
Ahmad Ghasemi-Ghalebahman ◽  
Javad Akbardoost ◽  
Yaser Ghaffari
Keyword(s):  
Fracture Toughness ◽  
Tangential Stress ◽  
Mixed Mode ◽  
Fracture Behavior ◽  
Process Zone ◽  
Maximum Tangential Stress ◽  
Mixed Mode Fracture ◽  
Mode Fracture ◽  
Stress Criterion ◽  
Maximum Tangential Stress Criterion

The aim of this study was to examine the effect of size on the mixed-mode fracture toughness of quasi-brittle nanocomposites with the help of modified maximum tangential stress criterion. The literature reveals that the effect of size on mixed-mode fracture behavior of brittle nanocomposites has not been well investigated previously using modified maximum tangential stress criterion. The studied nanocomposites were made of epoxy resin reinforced with 7 wt%, 20–30 nm nanosilica. The accuracy of the method was assessed by taking into account the high-order terms of Williams series expansion along with finite element over-deterministic method. To investigate the effect of size on fracture toughness, a number of three-point semi-circular bending tests with different radii and four angles of edge–crack orientation were conducted and subjected to mixed-mode loading. The size of fracture process zone and apparent fracture toughness ( Kc) were also evaluated as a function of sample size. Experimental results showed that the proposed approach can accurately predict the fracture behavior of studied nanocomposites.

Prediction of the path of unstable extension of internal and edge cracks

1980 ◽  
Vol 15 (4) ◽  
pp. 183-194 ◽  
Author(s):  
S K Maiti
Keyword(s):  
Energy Density ◽  
Tangential Stress ◽  
Strain Energy Density ◽  
Strain Energy ◽  
Experimental Studies ◽  
Stress Singularity ◽  
Maximum Tangential Stress ◽  
Stress Criterion ◽  
Maximum Tangential Stress Criterion ◽  
Edge Cracks

The criteria of strain energy density and maximum tangential stress have been applied to the entire stress field existing just before the onset of instability to predict the path of extension of both internal and edge cracks. The stress analysis has been carried out by a finite-element scheme employing the quarter point square-root stress singularity elements. In the case of internal cracks, the unstable paths based on both the criteria are in good agreement with the results available in the literature. Theoretical and experimental studies on edge crack extensions during bar shearing of brittle materials have facilitated a comparison, and it appears that, although the maximum tangential stress criterion may be applicable, the strain energy density criterion is unsuitable for this case.

The Parametric Study of the Crack Growth in the Lubricated Rolling-Sliding Contact Problems

2007 ◽  
Vol 348-349 ◽  
pp. 689-692
Author(s):  
Roki Potočnik ◽  
Jože Flašker ◽  
Bostjan Zafošnik ◽  
Srečko Glodež
Keyword(s):  
Crack Growth ◽  
Tangential Stress ◽  
Crack Path ◽  
Contact Problems ◽  
Sliding Contact ◽  
Maximum Tangential Stress ◽  
Hydraulic Pressure ◽  
Stress Criterion ◽  
Maximum Tangential Stress Criterion ◽  
T Stress

A two-dimensional numerical model is used to describe the crack path in the lubricated rolling-sliding contact problems. The model assumes that the crack is initiated in a pre-existing micro pit, which resulted from the crack growth on the surface of a gear tooth flank. The lubricated rolling-sliding contact problem is modelled using the Hertz theory of contact, the Coulomb's law of friction and hydraulic pressure mechanism with constant pressure which simulates the effect of lubricant trapped into the crack. Different load cases are used to simulate the moving of a contact load. The crack propagation path is evaluated by a maximum tangential stress criterion and modified maximum tangential stress criterion which considers the stress intensity factors KI and KII, the T-stress, the critical distance ahead the crack tip rc, and the stress on the crack surfaces. The computational results show that the consideration of the T-stress has a significant influence on the crack path in the lubricated rolling-sliding contact problems.

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