Estimation of ASTM E1921 Master Curve of Ferritic Steels From Instrumented Impact Test of CVN Specimens Without Precracking

2014 ◽  
Vol 3 (1) ◽  
pp. 20130079 ◽  
Author(s):  
P. R. Sreenivasan
Keyword(s):  
Master Curve ◽  
Impact Test ◽  
Ferritic Steels ◽  
Instrumented Impact Test

Use of Large Databases to Identify Trends in the Behavior of Ferritic Steels

2009 ◽  
Author(s):  
Mark T. EricksonKirk ◽  
MarjorieAnn EricksonKirk ◽  
Charles Rose ◽  
Xian J. Zhang
Keyword(s):  
Master Curve ◽  
Physical Models ◽  
Irradiation Damage ◽  
Transition Curve ◽  
Ferritic Steels ◽  
Systematic Effect ◽  
Mode Transition ◽  
Large Databases ◽  
Curve Model ◽  
New Evidence

In this paper we explore the crucial role played by the use of large databases in the identification, development, and refinement of models that describe the toughness behavior of ferritic steels. Specifically, we seek to emphasize and illustrate the point that when physical models are calibrated using large databases this process can reveal trends not previously seen, or foreseen. In support of this idea two examples are cited. First, the evidence for a CVE master curve in fracture mode transition is reviewed, as a counterpoint to the commonly held belief that each Charpy tanh transition curve is unique, with little commonality even within specific alloys, let alone across all ferritic steels. Second, new evidence is presented that the degree of prior hardening experienced by a ferritic steel has a systematic effect on the scatter exhibited by KJc data. This evidence suggests that the KJc Master Curve model, in which the scatter of KJc follows a Weibull distribution having a Kmin = 20 MPa√m and a slope (scatter magnitude) of 4, requires refinement, especially for the higher To values characteristic of steels that have been hardened by, for example, neutron irradiation damage.

Relationship Between Charpy V-Notch Impact Value and Fracture Mechanics Toughness: Added Value of Finite Element Analysis and Instrumented Impact Tests

2011 ◽  
Author(s):  
Philippe Thibaux ◽  
Filip Van den Abeele ◽  
Philippe Burlot
Keyword(s):  
Finite Element ◽  
Master Curve ◽  
Impact Test ◽  
Crack Arrest ◽  
Smooth Transition ◽  
Unstable Crack ◽  
Impact Tests ◽  
The Difference ◽  
Energy Dissipated ◽  
The Impact

Each structure is designed with resistance versus the fracture, which requires the knowledge of the fracture resistance of the material. If no fracture mechanics data of the material is available, a KJC can be inferred from the master curve approach. The master curve approach relates a fracture toughness of 100 MPAm1/2 to the impact transition temperature T27J with a shift of 18°C. Although this relationship was successfully applied to a large number of experiments, some steels deviate significantly from the previous relationship, which can even lead to non-conservative design. In the present paper, instrumented impact tests (Charpy V-Notch CVN) and compact tensile (CT) tests were performed on two materials, one thermomechanically (TM-) rolled and one normalized steel. The difference between T0 and T27J was found to be different for these materials. Furthermore, the normalized steel exhibits a smooth transition from brittle to ductile behaviour, while the TM-rolled material shows a very steep transition. Extra information is gained by combining the instrumentation of the impact test and the finite element simulations of both the CT and impact tests. From the instrumented tests, it is also possible to determine the load at unstable crack propagation, the amount of energy dissipated at that moment, the load at crack arrest and the energy dissipated after crack arrest. From the finite element simulation, one learns about the constraints ahead of the crack tip for both configurations. The investigation teaches us that the smooth transition of the normalized material is related to a high energy dissipated after crack arrest, while the TM-rolled material has a much lower crack arrest load. The difference between T0 and T27J is then discussed by decomposing the total energy in the impact test between crack initiation, propagation and arrest. It is compared with KJC, which determines the toughness at unstable crack propagation, by reviewing the literature and local stress states computed from finite element.

On the Use of the Notch Master Curve for Apparent Fracture Toughness Predictions of Notched Ferritic Steels Operating Within the Ductile-to-Brittle Transition Zone

2015 ◽  
Author(s):  
Sergio Cicero ◽  
Tiberio Garcia ◽  
Virginia Madrazo
Keyword(s):  
Fracture Toughness ◽  
Transition Zone ◽  
Fracture Resistance ◽  
Master Curve ◽  
Ferritic Steels ◽  
Brittle Transition ◽  
Apparent Fracture Toughness ◽  
Different Temperatures ◽  
Fracture Tests ◽  
Ductile To Brittle Transition

This paper presents the Notch-Master Curve as a model for the prediction of the apparent fracture toughness of ferritic steels in notched conditions and operating at temperatures corresponding to their ductile-to-brittle transition zone. The Notch-Master Curve combines the Master Curve of the material in cracked conditions and the notch corrections provided by the Theory of Critical Distances. In order to validate the model, the fracture resistance results obtained in fracture tests performed on notched CT and SENB specimens are presented. The results gathered here cover four ferritic steels (S275JR, S355J2, S460M and S690Q), three different notch radii (0.25 mm, 0.50 mm and 2.0 mm) and three different temperatures within the corresponding ductile-to-brittle transition zone. The results demonstrate that the Notch Master Curve provides good predictions of the fracture resistance in notched conditions for the four materials analyzed.

Validation of the Master Curve Approach With Various Welding Conditions: Groove Shapes, Heat Inputs and Welding Processes

2020 ◽  
Author(s):  
Jin Ho Lee ◽  
Ji Hoon Kim ◽  
Myung Hyun Kim
Keyword(s):  
Fracture Toughness ◽  
Master Curve ◽  
Impact Test ◽  
Structural Integrity ◽  
Charpy Impact ◽  
Test Sample ◽  
Charpy Impact Test ◽  
Theoretical Background ◽  
Reference Temperature ◽  
Welding Processes

Abstract Engineering critical assessment (ECA) is a procedure for evaluating the soundness of structures with flaws and has been widely applied for assessing the structural integrity. ECA procedure requires reliable fracture toughness data to assess the effect of defects. Ideal data are typically obtained from samples taken during construction of an engineering structure or from the structure afterward, but there are cases in which removal of the test samples is impossible due to the continued operation of the structure. To this end, Appendix J of the BS 7910 provides a procedure for estimating fracture toughness values from appropriate Charpy impact test data. However, the correlation between Charpy impact energy and fracture toughness is known to be overly conservative with not sufficient theoretical background in fracture mechanics perspective. In this regard, the revised BS 7910:2019 provides an improved method for calculating the reference temperature by applying the yield strength and the Charpy upper shelf energy based on empirical data. The target of this study is to validate the master curve approach in the modified BS 7910 for two common offshore grade steels with explicit considerations for various groove shapes, heat inputs and welding processes. For the purpose, the master curves are compared in terms of the reference temperature calculated from Charpy impact test according to BS 7910:2013 and the newly revised 2019 version of BS 7910. The modified master curve resulted in less conservative fracture toughness values anticipated from the decreased reference temperature. The estimated fracture toughness values exhibited a good correlation with experimentally obtained toughness values. The influence of various groove shapes, heat inputs and welding processes in estimating fracture toughness based on the master curve approach is discussed. In addition, the effect of impact test sample locations within weld metals toward estimated fracture toughness values is evaluated.

scholarly journals Investigation on Instrumented Impact Test and Loading Rate Dependency of Brittle Polymers.

1991 ◽  
Vol 57 (543) ◽  
pp. 2722-2726
Author(s):  
Hiroshi MIYATA ◽  
Isamu YAMAMOTO ◽  
Shuichi IGAKURA ◽  
Toshiro KOBAYASHI
Keyword(s):  
Impact Test ◽  
Loading Rate ◽  
Rate Dependency ◽  
Brittle Polymers ◽  
Instrumented Impact Test

scholarly journals Instrumented Impact Test of Ceramics

1986 ◽  
Vol 50 (2) ◽  
pp. 229-235 ◽  
Author(s):  
Toshiro Kobayashi ◽  
Mitsuo Niinomi ◽  
Yoshihiro Koide ◽  
Kenji Matsunuma
Keyword(s):  
Impact Test ◽  
Instrumented Impact Test
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