Comparison of Master Curve and Statistical Model Approach for Prediction of Fracture Toughness of ASTM A285 Steel

2004 ◽  
Author(s):  
Karthik Subramanian ◽  
Andrew J. Duncan
Keyword(s):  
Fracture Toughness ◽  
Statistical Models ◽  
Master Curve ◽  
Compact Tension ◽  
Standard Test ◽  
American Petroleum Institute ◽  
Test Method ◽  
Data Sets ◽  
Transition Range ◽  
American Society

The master curve approach was utilized to compare fracture toughness of American Society for Testing of Materials (ASTM) A285 as developed from Charpy v-notch (CVN) data and predictive statistical models. The master curves for each of the data sets were developed in accordance with American Society for Testing Materials Specification E 1921 (ASTM E1921, “Standard Test Method for Determination of Reference Temperature, T0, for Ferritic Steels in the Transition Range”), as prescribed by American Petroleum Institute Recommended Practice 579 (API-579, “Fitness for Service”). The results indicate that predictive statistical models developed from compact tension test results express a lower fracture toughness distribution when compared to CVN data.

Statistical Analysis of the ASME KIc Database

1998 ◽  
Vol 120 (1) ◽  
pp. 24-28 ◽  
Author(s):  
M. A. Sokolov
Keyword(s):  
Fracture Toughness ◽  
Distribution Function ◽  
Lower Bound ◽  
Weibull Distribution ◽  
Master Curve ◽  
Lower Boundary ◽  
Transition Range ◽  
Weibull Distribution Function ◽  
American Society ◽  
Function Models

The American Society of Mechanical Engineers (ASME) KIc curve is a function of test temperature (T) normalized to a reference nil-ductility temperature, RTNDT, namely, T – RTNDT. It was constructed as the lower boundary to the available KIc database. Being a lower bound to the unique but limited database, the ASME KIc curve concept does not discuss probability matters. However, a continuing evolution of fracture mechanics advances has led to employment of the Weibull distribution function to model the scatter of fracture toughness values in the transition range. The Weibull statistic/master curve approach was applied to analyze the current ASME KIc database. It is shown that the Weibull distribution function models the scatter in KIc data from different materials very well, while the temperature dependence is described by the master curve. Probabilistic-based tolerance-bound curves are suggested to describe lower-bound KIc values.

Theoretical Underpinning of the Constraint Effect Between Deeply Cracked C(T)- and SEN(B) Specimens

2005 ◽  
Author(s):  
Michael Ludwig
Keyword(s):  
Fracture Toughness ◽  
Standard Test ◽  
Test Method ◽  
Reference Temperature ◽  
Small Scale ◽  
Reference Solution ◽  
Constraint Effect ◽  
Local Approach ◽  
Transition Range ◽  
Weibull Stress

In the standard test method for the determination of the reference temperature T0 in the transition range, ASTM E 1921-03 [1], the remark is given that different specimen types could lead to discrepancies in the calculated T0 values. Especially C(T) and SEN(B) specimens indicate by experimental evidence that a 10 °C to 15 °C difference in T0 has been observed. In the course of the European research project VOCALIST [2] a ferritic RPV steel has been investigated by conducting numerous fracture toughness experiments as well as intensive numerical studies. A local approach model based on the Weibull stress has been developed and calibrated for this material [3]. For the calculation of the constraint effect between SEN(B) and C(T) specimens with a crack to ligament ratio of approx. 0.5 the model has been applied to predict the constraint effects on fracture toughness and the resulting theoretical difference in the reference temperature T0. For this purpose the according specimens have been calculated by several finite element models and a reference solution in the small scale yielding space allowed for the calculation of the “constraint free” reference transition temperature T0. By means of theoretical constraint functions derived from the Weibull stress model, the difference for each specimen compared to the reference solution could be calculated. From the results a theoretical difference of ΔT0 = 10°C between SEN(B) (lower value) and C(T) specimens (higher value) caused by the different crack tip constraint has been obtained. This value confirms the experimental observations.

Direct Use of the Fracture Toughness Master Curve in ASME Code, Section XI, Applications

2013 ◽  
Author(s):  
William Server ◽  
Russ Cipolla
Keyword(s):  
Fracture Toughness ◽  
Master Curve ◽  
Potential Problem ◽  
Standard Test ◽  
Test Method ◽  
Alternative Approach ◽  
Alternative Index ◽  
Asme Code ◽  
Technical Basis ◽  
Direct Use

The ASME Code, Section XI, has adopted the indirect use of the fracture toughness Master Curve to define an alternative index (RTT0) rather than RTNDT for using the Code KIC and KIa curves in Appendices A and G. RTT0 is defined as T0 + 19.7°C (T0 + 35°F), where T0 is the Master Curve reference temperature as defined in ASTM Standard Test Method E 1921. This alternative approach was first approved in ASME Code Case N-629 for Section XI and Code Case N-631 for Section III. Most recently this approach has been integrated directly into the Code, Section XI, and will be published in the 2013 Edition. When this alternative indexing approach was developed, it was recognized that the direct use of the Master Curve itself also could be used as an alternative to the Code KIC curve. A Code Case for the direct use of the fracture toughness Master Curve has been developed and has been presented to Section XI for approval. This paper provides the technical basis for using the fracture toughness Master Curve as an alternative to the Section XI KIC curve. An adjustment to the Master Curve at very low temperatures is included which alleviates a potential problem for low temperature overpressure (LTOP) protection setpoints as would be determined using the existing Code KIC curve.

Rational Determination of Lower-Bound Fracture Toughness Curves Using Master Curve Approach

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
Naoki Miura ◽  
Naoki Soneda ◽  
Shu Sawai ◽  
Shinsuke Sakai
Keyword(s):  
Fracture Toughness ◽  
Lower Bound ◽  
Master Curve ◽  
Surveillance Program ◽  
Data Sets ◽  
Ductile Brittle Transition Temperature ◽  
Asme Code ◽  
American Society ◽  
Reactor Pressure

The Master Curve gives the relation between the median of fracture toughness of ferritic steels and the temperature in the ductile–brittle transition temperature region. The procedure used to determine the Master Curve is provided in the current American Society for Testing and Materials (ASTM) E1921 standard. By considering the substitution of the alternative lower-bound curves based on the Master Curve approach for the KIc curves based on reference data sets in the present codes such as ASME Code Cases N-629 and N-631, the statistical characteristic should be well incorporated in the determination of the lower-bound curves. Appendix X4 in the ASTM standard describes the procedure used to derive the lower-bound curves; however, it appears to be addressed without sufficient consideration of the statistical reliability. In this study, we propose a rational determination method of lower-bound fracture toughness curves using the Master Curve approach. The method considers the effect of sample size in the determination of the tolerance-bound curve. The adequacy of the proposed method was verified by comparing the tolerance-bound curve with the fracture toughness database for national reactor pressure vessel (RPV) steels including plate and forging obtained from 4 T to 0.4 T C(T) specimens and 0.4 T SE(B) specimens. The method allows the application of the Master Curve using fewer specimens, which can coexist with the present surveillance program.

Experimental evaluation of fracture properties of bovine hip cortical bone using elastic–plastic fracture mechanics

2021 ◽  
pp. 1-10
Author(s):  
Waseem Ur Rahman ◽  
Rafiullah khan ◽  
Noor Rahman ◽  
Ziyad Awadh Alrowaili ◽  
Baseerat Bibi ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Plastic Deformation ◽  
Fracture Mechanics ◽  
Cortical Bone ◽  
Elastic Deformation ◽  
Compact Tension ◽  
J Integral ◽  
Elastic Plastic ◽  
American Society ◽  
Fracture Specimens

BACKGROUND: Understanding the fracture mechanics of bone is very important in both the medical and bioengineering field. Bone is a hierarchical natural composite material of nanoscale collagen fibers and inorganic material. OBJECTIVE: This study investigates and presents the fracture toughness of bovine cortical bone by using elastic plastic fracture mechanics. METHODS: The J-integral was used as a parameter to calculate the energies utilized in both elastic deformation (Jel) and plastic deformation (Jpl) of the hipbone fracture. Twenty four different types of specimens, i.e. longitudinal compact tension (CT) specimens, transverse CT specimens, and also rectangular unnotched specimens for tension in longitudinal and transverse orientation, were cut from the bovine hip bone of the middle diaphysis. All CT specimens were prepared according to the American Society for Testing and Materials (ASTM) E1820 standard and were tested at room temperature. RESULTS: The results showed that the average total J-integral in transverse CT fracture specimens is 26% greater than that of longitudinal CT fracture specimens. For longitudinal-fractured and transverse-fractured cortical specimens, the energy used in the elastic deformation was found to be 2.8–3 times less than the energy used in the plastic deformation. CONCLUSION: The findings indicate that the overall fracture toughness measured using the J-integral is significantly higher than the toughness calculated by the stress intensity factor. Therefore, J-integral should be employ to compute the fracture toughness of cortical bone.

Estimation of Master Curve Based RTTo Reference Temperature From CVN Data

2005 ◽  
Author(s):  
Kim R. W. Wallin ◽  
Gerhard Nagel ◽  
Elisabeth Keim ◽  
Dieter Siegele
Keyword(s):  
Fracture Toughness ◽  
Pressure Vessel ◽  
Brittle Failure ◽  
Master Curve ◽  
Simple Relation ◽  
Systematic Evaluation ◽  
Data Sets ◽  
Irradiation Embrittlement ◽  
Pressure Vessel Steels ◽  
Asme Code

The ASME code cases N-629 and N-631 permits the use of a Master Curve-based index temperature (RTTo ≡ T0 + 19.4°C) as an alternative to traditional RTNDT-based methods of positioning the ASME KIc, and KIR curves. This approach was adopted to enable use of Master Curve technology without requiring the wholesale changes to the structure of the ASME Code that would be needed to use all aspects of Master Curve technology. For the brittle failure analysis considering irradiation embrittlement additionally a procedure to predict the adjustment of fracture toughness for EOL from irradiation surveillance results must be available as by NRC R.G. 1.99 Rev. 2 e.g.: ART = Initial RTNDT + ΔRTNDT + Margin. The conservatism of this procedure when RTNDT is replaced by RTTo is investigated for western nuclear grade pressure vessel steels and their welds. Based on a systematic evaluation of nearly 100 different irradiated material data sets, a simple relation between RTToirr, RTToref and ΔT41JRG is proposed. The relation makes use of the R.G. 1.99 Rev. 2 and enables the minimizing of margins, necessary for conventional correlations based on temperature shifts. As an example, the method is used to assess the RTTo as a function of fluence for several German pressure vessel steels and corresponding welds. It is shown that the method is robust and well suited for codification.

ASTM E 1559 Method for Measuring Material Outgassing/Deposition Kinetics

1995 ◽  
Vol 38 (1) ◽  
pp. 19-28
Author(s):  
J. Garrett ◽  
A. Glassford ◽  
J. Steakley
Keyword(s):  
Air Force ◽  
High Vacuum ◽  
Standard Test ◽  
Test Method ◽  
Deposition Kinetics ◽  
Standard Test Method ◽  
Typical Data ◽  
American Society ◽  
Kinetics Of ◽  
Measurement Approach

The American Society for Testing and Materials (ASTM) has published a new standard test method for characterizing time and temperature dependence of material outgassing kinetics and the deposition kinetics of outgassed species on surfaces at various temperatures. This new ASTM standard, E 1559,1 uses the quartz crystal microbalance (QCM) collection measurement approach. The test method was originally developed under a program sponsored by the U.S. Air Force Materials Laboratory to create a standard test method for obtaining outgassing and deposition kinetics data for spacecraft materials. Standardization by ASTM recognizes that the method has applications beyond aerospace. In particular, the method will provide data of use to the electronics, semiconductor, and high vacuum industries. This paper describes the ASTM E 1559 test method and presents some typical data. the paper also describes the Lockheed ASTM E 1559 test apparatus.

Parameters on Fracture Strength of Sea Ice

1983 ◽  
Vol 105 (1) ◽  
pp. 12-16 ◽  
Author(s):  
N. Urabe ◽  
A. Yoshitake ◽  
T. Iwasaki ◽  
M. Kawahara
Keyword(s):  
Fracture Toughness ◽  
Sea Ice ◽  
Strain Rate ◽  
Fracture Strength ◽  
Test Procedure ◽  
Standard Test ◽  
Test Method ◽  
Beam Specimen ◽  
Crushing Strength ◽  
Brackish Ice

Compressive crushing strength on brackish ice and sea ice and fracture toughness value on sea ice were measured as parameters associated with fracture strength of ice. The compressive crushing strength depends on salinity, temperature and strain rate. At constant salinity and temperature, the strength increased with increase in strain rate and reached maximum value at about a strain rate of 10−3 s−1, then decreased with increase in strain rate. An empirical equation to estimate the compressive crushing strength was derived as a function of brine volume, temperature and strain rate. As far as fracture toughness is concerned, a simplified test procedure on notched cantilever beam specimen was developed in order to avoid complicated manipulation in field conditions. The fracture toughness value (KIC) coincided well with the value obtained from fracture toughness tests conducted in conformity with the standard test method.

Determination of the Fracture Toughness Parameters for an MDF Cement Composite

1985 ◽  
Vol 64 ◽  
Author(s):  
M. Arzamendi ◽  
R. L. Sierakowski ◽  
W. E. Wolfe
Keyword(s):  
Fracture Toughness ◽  
Cement Composite ◽  
Compact Tension ◽  
Test Methods ◽  
Standard Test ◽  
Elastic Behavior ◽  
Hardened Cement ◽  
Linear Elastic ◽  
Toughness Testing

ABSTRACTThe experimental results of fracture toughness testing of a Macro Defect (MDF) Free cement are presented. The material, a hydraulic cement with hydrolyzed polyvinyl polymers, behaves much like a hardened ceramic with measured maximum compressive and tensile strengths of 380 MN/m2 and 69 MN/m2 respectively. Fracture toughness tests were performed on compact tension (CT) and single edge notched beam (SENB) specimens cut from test panels which were supplied in 3mm, 5mm and 10mm thicknesses. The results were evaluated with respect to the fracture toughness parameter Kic using a modification of standard test methods as determined by observed natural behavior. The MDF material exhibited an essentially linear elastic behavior with a fracture toughness slightly higher than typical values recorded for hardened cement paste.

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.

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