Evaluation of Fracture Toughness (JIC) Using Single Specimen Fracture Test Augmented by Finite Element Analysis

1983 ◽  
Vol 105 (1) ◽  
pp. 8-12 ◽  
Author(s):  
R. D. Streit
Keyword(s):  
Fracture Toughness ◽  
Crack Length ◽  
Compact Tension ◽  
Test Results ◽  
Single Specimen ◽  
Fracture Test ◽  
Flow Properties ◽  
Element Analysis ◽  
Extension Curve ◽  
Tension Fracture

Fracture toughness is evaluated using the combination of results from a single compact tension fracture test and computationally developed key-curves. The key-curves—a family of load-deflection curves for the test specimen with different length cracks—were developed using the tensile flow properties of the material. By overlaying the experimental test results on these curves the crack length and crack growth during the test can be deduced. The value of J for each crack length is then evaluated from the experimental load-deflection data. The J versus crack extension curve is plotted and JIC evaluated. The method is applied to the evaluation of the toughness of depleted uranium and is shown to substantially reduce the scatter often observed in the J versus Δa data.

Influence of Specimen Type, Crack Length and Evaluation Method on Quasi-Static and Dynamic Fracture Toughness Properties

2009 ◽  
Author(s):  
Conrad Zurbuchen
Keyword(s):  
Fracture Toughness ◽  
Crack Length ◽  
Evaluation Method ◽  
Mechanical Test ◽  
Compact Tension ◽  
Dynamic Fracture Toughness ◽  
Test Results ◽  
Evaluation Standards ◽  
Specimen Type ◽  
Surveillance Specimens

This paper provides a comparison of the influence of specimen type (single edge bend (SE(B)) specimen vs. compact tension C(T) specimen), specimen dimensions (crack length ratio a/W, thickness B) and the effect of the loading rate on fracture toughness properties. In the lower ductile-brittle transition region the quasi-static Master Curve (MC) reference temperature T0 is evaluated according to ASTM E 1921-08ae1 and the dynamic MC T0 according to the Swiss guideline HSK-AN-425, which is compared with a modified ASTM E 1921-08ae1 approach. The ductile behaviour was evaluated by quasi-static JR curve testing in which the applicability of several evaluation standards are compared (ASTM E 1820-08, ISO 12135, ESIS-P2). Quasi-static and dynamic MC temperatures T0 deviate by up to 68 K. SE(B) specimens with shorter crack lengths (a/W = 0.3) than prescribed by ASTM E 1921 yield the same T0 as specimens with a/W = 0.5. Thus, such short crack surveillance specimens are also suitable for fracture mechanical assessments. SE(B) specimens of B = 0.4T (1T = 1 inch) up to 3.2T show comparable T0, proving the transferability of fracture mechanical test results of small surveillance specimens to heavy-walled RPV structures.

Experimental Investigation on Relative Crack Length For Fracture Toughness of Concrete

2010 ◽  
Vol 146-147 ◽  
pp. 1524-1528 ◽  
Author(s):  
Xue Zhi Wang ◽  
Zong Chao Xu ◽  
Zhong Bi ◽  
Hao Wang
Keyword(s):  
Fracture Toughness ◽  
Experimental Investigation ◽  
Crack Length ◽  
Fracture Toughness Test ◽  
Test Results ◽  
Toughness Test ◽  
Wedge Splitting Test ◽  
Splitting Test ◽  
Wedge Splitting

The wedge splitting test specimens with three series of different relative crack length were used to study the influences of relative crack length on the fracture toughness of common concrete. The suitable formulation for fracture toughness of concrete with different relative crack length was gotten on comparing between fracture toughness test results and computation results of the model developed from Hu formula.

Fracture Toughness Behaviour of 316L Stainless Steel Samples Manufactured Through Selective Laser Melting

2018 ◽  
Author(s):  
Catrin M. Davies ◽  
Ruijan Zhou ◽  
Olivia Withnell ◽  
Richard Williams ◽  
Tobias Ronneberg ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Selective Laser Melting ◽  
316L Stainless Steel ◽  
Compact Tension ◽  
Crack Plane ◽  
Laser Melting ◽  
Growth Plane ◽  
Toughness Testing ◽  
Tension Fracture

Selective laser melting (SLM) is a relatively new manufacturing technique which offers many benefits. However the utilisation of SLM manufactured components depends on the assurance of their integrity during operation. Fracture toughness testing (JIC) has been performed on as-built compact tension fracture mechanics samples manufactured in three orthogonal directions. When the crack growth plane was transverse to the interface of the build layers, the fracture toughness values were found to be similar to those manufactured using conventional techniques. However, the fracture toughness is significantly reduced when the crack plane is parallel to the interface of the build layers. Simple heat treatments have been performed on Charpy fracture samples and the resulting impact energy values indicate that the fracture toughness of a component may be improved by heat treatment.

Effects of Crack Front Curvature on J and CTOD Determination in Fracture Toughness Specimens by FEA

2013 ◽  
Author(s):  
Emily K. Hutchison ◽  
Henryk G. Pisarski
Keyword(s):  
Fracture Toughness ◽  
Crack Length ◽  
Crack Front ◽  
Weighted Average ◽  
Maximum Deviation ◽  
Element Analysis ◽  
Straight Crack ◽  
Curved Crack ◽  
Average Crack ◽  
Senb Specimen

This paper investigates the effect of crack curvature on a single edge notched bend (SENB) specimen using finite element analysis (FEA). The variations of J and CTOD were studied through the thickness of the specimen for different levels of crack curvature. Five different curved crack fronts were considered, with the same weighted average crack length based on BS 7448. The levels of curvature varied from a straight crack front to a maximum deviation of 25% from the average crack length. The findings can be used to recommend more comprehensive crack curvature qualification checks for SENB tests and potentially provide improved estimates of fracture toughness when curvature is greater than allowed by the standard.

Finite Element Analysis of Dry Shrinkage of Fiber Cement Mortar

2014 ◽  
Vol 590 ◽  
pp. 312-315
Author(s):  
Wei Hong Xuan ◽  
Pan Xiu Wang ◽  
Yu Zhi Chen ◽  
Xiao Hong Chen
Keyword(s):  
Fracture Toughness ◽  
Cement Mortar ◽  
Polypropylene Fiber ◽  
Polypropylene Fibers ◽  
Test Results ◽  
Ansys Software ◽  
Element Analysis ◽  
Cement Based Materials ◽  
Dry Shrinkage ◽  
Good Agreement

The dry shrinkage deformation of polypropylene fiber mortar was analyzed by ANSYS software and compared with experiment value in this paper. The error of the calculated and experimental results in the 14 days and 28 days are 7.8% and 10.5%. It can be found that the calculated results are in good agreement with test results. The results indicate that the dry shrinkage value of polypropylene fiber mortar is lower than ordinary mortar. Adding polypropylene fibers can inhibit the process of cracking and improve the fracture toughness of cement-based materials.

Additional Data Concerning French PWR RPV Steel to Evaluate the Relevance of a Size Effect Correction on Toughness in the Ductile-to-Brittle Transition

2014 ◽  
Author(s):  
C. Jacquemoud ◽  
I. Delvallée-Nunio ◽  
M. Nédélec ◽  
F. Balestreri
Keyword(s):  
Fracture Toughness ◽  
Size Effect ◽  
Crack Length ◽  
Compact Tension ◽  
Ferritic Steels ◽  
Transition Range ◽  
Brittle Transition ◽  
Reference Length ◽  
Rpv Steel ◽  
Ductile To Brittle Transition

In the ductile-to-brittle transition range of ferritic steels, fracture toughness exhibits a size effect. Up to now, in the safety demonstration of the French Reactor Pressure Vessel (RPV) integrity, a size effect correction has been considered by the operator to take into account fracture toughness variation of ferritic steels with crack length. The correction consists in increasing the toughness estimated on the RCC-M curve by a factor which depends on a reference length and on the crack length considered. IRSN has already examined the relevance of this correction through statistical analysis of toughness results coming from two ferritic steel databases. To complete its evaluation on French RPV steel, IRSN has supported a large experimental campaign on 16MND5 steel at different temperatures in the ductile-to-brittle transition (from −150°C to −50°C), including tests on various Compact Tension (CT) specimen geometries. Specimens with semi-elliptical crack have been also considered. The results confirm the observations made in its previous study: a size effect exists on mean or median toughness, for the latter more or less in accordance with Beremin theory. Nevertheless, the minimum toughness appears to be independent of the specimen geometry. This indicates that the use of a size effect correction on minimum toughness is not relevant.

Adjustments to Master Curve Methodology and Development of Fracture Toughness Estimation

2011 ◽  
Author(s):  
R. S. Kulka
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Driving Force ◽  
Master Curve ◽  
Structural Components ◽  
Fracture Test ◽  
Element Analysis ◽  
Master Curve Method ◽  
Curve Method ◽  
Constraint Effects

In conventional fracture mechanics assessments, there is often an inadequate treatment of in-plane constraint effects on the apparent toughness of structural components, leading to significant conservatism. Modifications to the Master Curve method, to account for these effects, have previously been suggested. A study of these proposed modifications has identified that less conservative toughness estimates could be made from the analysis of fracture mechanics test specimens. An approach has been developed for allowing a comparison of a variation of fracture toughness values throughout a component, to a variation of the localised effective driving force. Cracked-body finite element analysis has been used to assess fracture test specimens with varying levels of in-plane constraint, to provide fracture mechanics data for use with the approach that has been developed.

Fracture Toughness of Aged Stainless Steel Primary Piping Welds Evaluated by Multiple and Single-Specimen Methods

1993 ◽  
Vol 115 (2) ◽  
pp. 201-206 ◽  
Author(s):  
F. H. Huang
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Electric Potential ◽  
Compact Tension ◽  
Test Facility ◽  
Single Specimen ◽  
Critical Fracture ◽  
Toughness Testing ◽  
Steel Welds

Fracture toughness testing was conducted on compact tension specimens cut from the Fast Flux Test Facility primary piping materials of 16-8-2 and 308 stainless steel welds aged at 427 and 482°C for 20,000 and 50,000 hr. The ductile fracture behavior of the materials was characterized at 205, 427, and 482°C using multiple and electric-potential single-specimen techniques. Electric-potential data were used to caculate crack extensions via an electric-potential calibration equation for the construction of J-R curves. Results demonstrate that the critical fracture-toughness values are in good agreement with those from the multiple-specimen method. Results showed that 20,000-hr aging caused more than 35 percent degradation in fracture resistance, and 50,000-hr aging resulted in a slight increase in Jc for 16-8-2 stainless steel welds. It was found that the fracture toughness levels of the primary piping after long-term aging were high and adequate at the aging temperatures and that fuel handling temperature, nonductile fracture was not expected to occur in these materials.

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