Evaluation of J-Integral and COD for Compact Tension Specimen

1981 ◽  
pp. 89-98
Author(s):  
M. Shiratori ◽  
T. Miyoshi
Keyword(s):  
Compact Tension ◽  
Compact Tension Specimen ◽  
J Integral ◽  
Tension Specimen

Comparison of J-Integral Values and J-R Curves Between Carbon Steel Compact Tension Specimen and Pipe Specimen

2004 ◽  
Author(s):  
Masahiro Takanashi ◽  
Satoshi Izumi ◽  
Shinsuke Sakai ◽  
Naoki Miura
Keyword(s):  
Fracture Toughness ◽  
Carbon Steel ◽  
Crack Initiation ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Small Scale ◽  
Outer Diameter ◽  
J Integral ◽  
Tension Specimen ◽  
Elastic Plastic

In the present study, the transferability of elastic-plastic fracture toughness from a small-scale to a large-scale specimen was experimentally confirmed for carbon steel pipe with mild toughness. Fracture toughness tests were carried out on a pipe specimen 318.5 mm in outer diameter, 10.3 mm in thickness and having a through-wall crack, and also on a compact tension specimen 9.7mm in thickness, 25.4 mm in width, that had been cut out from the pipe specimen. Test results indicated the J-integral value of the pipe specimen at the crack initiation to be nearly twice that of the CT specimen. Finite element analysis conducted on the two specimens indicated this difference to arise primarily from the constraint near the crack front. Discussion was also made of the effects of crack orientation on elastic-plastic fracture toughness of CT specimens. The J-integral value at crack initiation in the specimen whose crack direction coincided with the pipe axial was found to be almost 54 % more than for specimens whose crack direction was circumferential.

J-Integral Analysis of the Compact Tension Specimen

1989 ◽  
Vol 111 (2) ◽  
pp. 138-144 ◽  
Author(s):  
A. Zahoor
Keyword(s):  
Limit Load ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
J Integral ◽  
Resistance Curve ◽  
Tension Specimen ◽  
Specimen Width ◽  
Present Solution ◽  
Resistance Curves ◽  
Η Factor

A J-integral solution is presented for the compact tension specimen. The solution allows analysis for crack lengths greater than 20 percent of the specimen width. Unlike previous solutions that were based on the assumptions of full ligament yielding, deeply cracked specimen, or limit load, this paper derives a J solution that does not require such assumptions. Solutions are presented for both the deformation theory J and modified J, JM. These solutions are suitable for J-resistance curve development. A relationship between the plastic and the elastic η factor is presented. A comparison of the present solution with earlier solutions indicates that the J for those solutions is underestimated for a/W below 0.5. Numerical results show that Jd and JM resistance curves are closer than previously obtained. A criterion for extrapolating J-resistance curve is proposed. A relationship for scaling load-displacement curves suitable for key curve analysis is also presented.

Non-Linear Fatigue Fracture Analysis of Composite Laminates

2009 ◽  
Vol 17 (6) ◽  
pp. 371-377 ◽  
Author(s):  
V. Rizov
Keyword(s):  
Crack Growth ◽  
Fatigue Fracture ◽  
Composite Laminates ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Damage Analysis ◽  
J Integral ◽  
Tension Specimen ◽  
Linear Deformation ◽  
Non Linear

In this paper, results of an experimental and numerical investigation of the effects of non-linear deformation on the fatigue crack growth in composite laminates are presented and discussed. Mode I fatigue fracture experiments are carried out on extended compact tension specimens under sinusoidal load control at a frequency of 4 Hz. The fatigue fracture test data are analysed using a power law relationship between the crack growth rates and the range of the path-independent J-integral. A two- dimensional finite element model of the extended compact tension specimen is set up in order to compute the J-integral values. The model is coupled with damage analysis in order to study the effect of non-linear deformation on the fatigue fracture performance. The damage analysis is based on the Tsai-Wu failure criterion. The non-linear model is verified by carrying out comparisons between the simulated mechanical behaviour of the extended compact tension specimen and the measured one. The damage distribution within the specimen is analyzed. The J-integral is computed over paths surrounding the crack tip and not crossing the damage zone. It is shown that taking into account the damage behaviour improves the fatigue fracture resistance, which is attributed to increased strain energy dissipation as a result of non-linear deformation.

Influence of Sulfur Content on the Fracture Toughness Properties of 2 1/4 Percent Cr-1 Percent Mo Steel

1976 ◽  
Vol 98 (2) ◽  
pp. 135-142 ◽  
Author(s):  
J. F. Copeland
Keyword(s):  
Fracture Toughness ◽  
Sulfur Content ◽  
Detrimental Effect ◽  
Crack Opening ◽  
Analytical Techniques ◽  
Compact Tension ◽  
Compact Tension Specimen ◽  
Tension Specimen ◽  
Microvoid Coalescence ◽  
Opening Displacement

The effects of sulfur content on the fracture toughness properties of 2 1/4Cr-1 Mo steel were evaluated at test temperatures above, at, and below the nil ductility transition temperature (NDTT) of −23°C (−10°F). Small, 12.7-mm (0.5-in.) thick compact tension specimen results were combined with J-integral, Equivalent Energy, and Crack Opening Displacement analytical techniques to provide KIc results up to 22°C (72°F). It was found that the sulfur content of this steel has a large detrimental effect on KIc at the NDTT and above, where microvoid coalescence is the fracture mode. Sulfur has no significant effect at −73°C (−100°F) where cleavage occurs. These results also indicate that the higher Charpy V-notch energy at NDTT, shown by lower sulfur steels, is translatable into increased fracture resistance.

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