Influence of thickness on critical crack opening displacement (COD) and J values

1981 ◽  
Vol 17 (4) ◽  
pp. 427-440 ◽  
Author(s):  
H. G. Pisarski
Keyword(s):  
Crack Opening Displacement ◽  
Crack Opening ◽  
Opening Displacement ◽  
Critical Crack ◽  
Critical Crack Opening

Test for Crack Opening Displacement of Steel Fiber Reinforced Concrete under Three-Point Bending

2010 ◽  
Vol 36 ◽  
pp. 157-161 ◽  
Author(s):  
Tin Gyi Zhang ◽  
Yuan Bao Leng ◽  
Dan Ying Gao
Keyword(s):  
Crack Opening Displacement ◽  
Crack Opening ◽  
Mouth Opening ◽  
Crack Tip ◽  
Crack Mouth Opening Displacement ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Critical Crack ◽  
Critical Crack Opening ◽  
Crack Tip Opening

Based on the principle of electrical measurement method, the clip gauge was made to measure the crack opening displacement (COD).Through the three-point bending test on the specimens of steel fiber reinforced high strength concrete (SFHSC), the effect of the fiber volume fraction (ρf) upon the critical crack opening displacement (the critical crack tip opening displacement and the critical crack mouth opening displacement) was studied. The result shows that the effect of ρf on mouth-tip ratio (the ratio of critical crack mouth opening displacement to critical crack tip opening displacement) can reflect its effect upon the critical crack opening displacement. According to the geometrical relationship between the initial crack length and the critical crack opening displacement，calculation method for the initial crack length was proposed. Based on the test result, the formula was established for calculating the critical crack tip opening displacement.

The crack opening displacement approach to fracture mechanics in yielding materials

1966 ◽  
Vol 1 (2) ◽  
pp. 145-153 ◽  
Author(s):  
F. M. Burdekin ◽  
D. E. W. Stone
Keyword(s):  
Fracture Mechanics ◽  
Crack Opening Displacement ◽  
Crack Opening ◽  
Opening Displacement ◽  
Critical Crack ◽  
Absolute Size ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
Critical Crack Opening ◽  
Displacement Approach

An introduction is given to the fracture mechanics approach employing the concept of crack opening displacement for application to situations in which linear elastic fracture mechanics is invalidated by yielding. The hypothesis of a critical crack opening displacement to fracture has been examined experimentally using mild steel specimens of vastly differing dimensions. Subsidiary experiments have been carried out to define the factors responsible for the apparent effect of absolute size on the results. A theoretical analysis simulates elastic-plastic conditions to give a relationship between applied stresses and strains, crack length, and crack opening displacement.

Evaluation of Wedge Splitting Fracture Tests Using the Double-K Model: Analysis of the Effect of Hemp Fibre Dosage and Length in Concrete Specimens

2016 ◽  
Vol 249 ◽  
pp. 142-146
Author(s):  
Hana Šimonová ◽  
Ivana Havlíková ◽  
Jakub Sobek ◽  
Alaa Abdulrahman ◽  
Zbyněk Keršner ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Crack Propagation ◽  
Crack Opening Displacement ◽  
Crack Opening ◽  
Opening Displacement ◽  
Critical Crack ◽  
Hemp Fibre ◽  
Fracture Tests ◽  
Critical Crack Opening ◽  
Wedge Splitting

This paper deals with the results obtained from the employment of a selected fracture model to evaluate wedge splitting fracture tests carried out on hemp fibre concrete specimens. The research work was focused mainly on the effect of the dosage and length of hemp fibres on the initiation part of crack propagation in concrete specimens, and on critical crack opening displacement. Concrete mixtures with different volumetric dosages (0.5, 1.0 and 2.0 %) and fibre lengths (10, 20 and 40 mm) were prepared, and six identical specimens were cast from each mixture. Specimens were also cast from a reference mixture, which was without fibres. The specimens were provided with an initial notch and tested using the wedge splitting test method. Load versus crack mouth opening displacement diagrams were recorded during testing and (after data filtering and appropriate modifications) subsequently evaluated using the Double-K fracture model. This model allows the evaluation of two material parameters – the initiation fracture toughness, which defines the onset of stable crack propagation, and the unstable fracture toughness, which defines the onset of unstable cracking or failure. Finally, the critical crack opening displacement was determined with the assumption of the bilinear function of softening in tension.

Finite Element Analysis of Brittle Cracking due to Single Grit Rotating Scratch

2003 ◽  
Vol 70 (1) ◽  
pp. 147-151 ◽  
Author(s):  
G. Subhash ◽  
W. Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Crack Opening ◽  
Damage Zone ◽  
Depth Of Cut ◽  
Opening Displacement ◽  
Element Analysis ◽  
Critical Crack ◽  
Critical Crack Opening ◽  
Brittle Material Removal

Finite element analysis of single grit rotating scratch on brittle materials was conducted using an “elastic-plastic-cracking” (EPC) model. The brittle material removal mechanism was modeled based on a critical crack-opening displacement criterion. It was found that the tangential and normal force profiles as well as the damage morphology observed in scratch experiments were fully captured by the EPC model. The results revealed that the induced damage zone size increases linearly with a brittleness parameter EY/σf21/3 as well as the maximum depth of cut.

The Relationship Between Stress Intensity Factor, Crack Opening Displacement and J-Integral in Zr-2.5 Percent Nb

1980 ◽  
Vol 102 (1) ◽  
pp. 97-100 ◽  
Author(s):  
L. A. Simpson
Keyword(s):  
Stress Intensity ◽  
Crack Opening Displacement ◽  
Crack Extension ◽  
Crack Opening ◽  
J Integral ◽  
Opening Displacement ◽  
Crack Face ◽  
Critical Crack ◽  
Wide Range ◽  
The Relationship

Crack opening displacement (COD) has been determined in Zr-2.5 percent Nb over a wide range of applied stress intensity, K. Prior to initiation of crack extension, COD was determined from measurements of stretch zones in specimens which had undergone hydrogen-induced, sub-critical crack growth. In post initiation measurements (during slow stable crack extension), COD was determined from crack face displacement. Both methods were self consistent and depended on the plastic-zone-corrected K in accordance with the Wells equation. The J-integral was also determined during stable crack extension using the method of Garwood, et al. The results are consistent with the COD measurements based on theoretical relationships between the two crack tip parameters.

The Criterion of Variable COD and CTOA for Numerical Simulation with Aluminum Alloy 2524

2011 ◽  
Vol 261-263 ◽  
pp. 707-711
Author(s):  
Li Jun Shi ◽  
Li Zhong Jiang ◽  
Bang Cheng Yang
Keyword(s):  
Aluminum Alloy ◽  
Crack Opening ◽  
Opening Angle ◽  
Welding Parameters ◽  
Fracture Parameter ◽  
Opening Displacement ◽  
Critical Crack ◽  
Friction Stir ◽  
Critical Crack Opening ◽  
Performance Research

The performance research of Friction Stir Weld’s Joints of Aluminum Alloy under different welding parameters is very necessary and valuable in the engineering. Two points is proposed in this paper. One is the new fracture criterion using the function curve of the value of critical crack opening displacement (|CODc|) as a fracture parameter, the other is using critical crack opening angle (CTOA) as a fracture parameter.

A New Methodology for Estimating Fracture Criterion of Thin Sheets

2009 ◽  
Vol 417-418 ◽  
pp. 305-308
Author(s):  
Kalyan Kumar Ray ◽  
Ashmita Patra ◽  
Debashish Bhattacharjee
Keyword(s):  
Fracture Toughness ◽  
Crack Opening ◽  
Specimen Thickness ◽  
Interstitial Free ◽  
Thin Sheets ◽  
If Steel ◽  
Opening Displacement ◽  
Critical Crack ◽  
Suggested Technique ◽  
Critical Crack Opening

A simple and reliable method has been proposed for determining fracture toughness of thin sheets. The principle of the method considers that critical crack opening displacement (c) corresponds to a specific amount of load drop during fracture toughness tests. The suggested technique yields c value for an interstitial free (IF) steel as 2.04 mm in excellent correspondence with an indirect estimate of 1.97 mm from the popular energy extrapolation technique. The magnitude of c for IF steel sheets is found to decrease with decreasing thickness in agreement with the expected variation of this criterion with specimen thickness in gross yielding fracture mechanics (GYFM) regime.

Size Effect of Concrete in Uniaxial Tension

2008 ◽  
Vol 41-42 ◽  
pp. 227-232 ◽  
Author(s):  
Hiroshi Akita ◽  
Dariusz Alterman ◽  
Hideo Koide
Keyword(s):  
Tensile Strength ◽  
Size Effect ◽  
Fracture Energy ◽  
Uniaxial Tension ◽  
Size Dependence ◽  
Crack Opening ◽  
Opening Displacement ◽  
Critical Crack ◽  
Tension Softening ◽  
Critical Crack Opening

In order to investigate the size effect of concrete, four sizes of rectangular prisms were tested in uniaxial tension. The cross sections of the prisms were 50x100mm, 100x100mm, 200x100mm and 400x100mm. The concrete was an ordinary one with the compressive strength of 34 MPa and the maximum aggregate size of 20mm. Notches were applied on four side faces and secondary flexure was completely eliminated during the test in order to obtain the exact nominal tensile strength. The size effect was analyzed by four factors, namely tensile strength, fracture energy, critical crack opening displacement and tension softening curves. Clear size dependence was observed in critical crack opening displacement and initial convexity of tension softening curves, and a slight size dependence was observed in tensile strength. On the other hand, size effect was unclear in fracture energy and other part of tension softening curves because of their scatters.

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