Evaluation of Fracture Toughness Test Data for Multilayer Dissimilar Joint Welds Using a Weibull Stress Model

2012 ◽  
pp. 357-376
Author(s):  
Yasuhito Takashima ◽  
Mitsuru Ohata ◽  
Masaru Seto ◽  
Yoshitomi Okazaki ◽  
Fumiyoshi Minami
Keyword(s):  
Fracture Toughness ◽  
Test Data ◽  
Dissimilar Joint ◽  
Fracture Toughness Test ◽  
Stress Model ◽  
Toughness Test ◽  
Weibull Stress

Evaluation of Fracture Toughness Test Data for Multilayer Dissimilar Joint Welds Using a Weibull Stress Model

2012 ◽  
Vol 9 (3) ◽  
pp. 103979
Author(s):  
Yasuhito Takashima ◽  
Mitsuru Ohata ◽  
Masaru Seto ◽  
Yoshitomi Okazaki ◽  
Fumiyoshi Minami
Keyword(s):  
Fracture Toughness ◽  
Test Data ◽  
Dissimilar Joint ◽  
Fracture Toughness Test ◽  
Stress Model ◽  
Toughness Test ◽  
Weibull Stress

Fracture Assessment of Welded Joint With Geometrical Discontinuity Using the Weibull Stress

2006 ◽  
Author(s):  
Satoshi Igi ◽  
Takahiro Kubo ◽  
Masayoshi Kurihara ◽  
Fumiyoshi Minami
Keyword(s):  
Fracture Toughness ◽  
Brittle Fracture ◽  
Welded Joint ◽  
Fracture Toughness Test ◽  
Geometrical Condition ◽  
Stress Criterion ◽  
Toughness Test ◽  
Fracture Assessment ◽  
Geometrical Discontinuity ◽  
Weibull Stress

Recently the Weibull stress is used as a fracture driving force parameter in fracture assessment. The Weibull stress is derived from a statistical analysis of local instability of micro cracks leading to brittle fracture initiation. The critical Weibull stress is expected to be a critical parameter independent of the geometrical condition of specimens. Fracture toughness test using 3-point bending and tensile tests of welded joint specimens with geometrical discontinuity were conducted in order to study the applicability of fracture assessment procedure based on Weibull stress criterion. Steel plates prepared for this study had tensile strength of 490 MPa for structural use. Two kinds of welded joint specimens, “one-bead welded joint” and “multi-pass welded joint” were prepared for fracture toughness test by using gas metal are welding. In tensile test specimen, corner flaws were introduced at the geometrical discontinuity part at where stress concentration is existed. Three dimensional elastoplastic finite element analyses were also carried out using the welded joint specimen models in order to calculate the Weibull stress. The critical loads for brittle fracture predicted by the Weibull stress criterion from CTOD test results of one-bead and multi-pass welded joint specimens show fairly good agreement with experimental results of welded joint specimens with geometrical discontinuity.

Issue of Application for the Pre-Cracked Charpy Specimens to Estimate WWER-1000 RPV Metal Embrittlement

2016 ◽  
Author(s):  
Volodymyr M. Revka ◽  
Liudmyla I. Chyrko
Keyword(s):  
Fracture Toughness ◽  
Test Data ◽  
Charpy Impact ◽  
Pressure Vessels ◽  
Reference Temperature ◽  
Fracture Toughness Test ◽  
Toughness Test ◽  
Standard Specimens ◽  
High Level ◽  
Reactor Pressure

In this study the analysis of fracture toughness test data has been performed in terms of estimation of the proper T0 value for several WWER-1000 RPV materials in unirradiated condition. The surveillance test data for the standard and reconstituted specimens were included in the analysis. It was found that a reference temperature T0 for reconstituted specimens is 31°C higher on average in comparison to the standard specimens. The possible reason is a high level of the stress intensity factor Kmax during the cycle at the stage of completion of crack tip sharpening for standard specimens. Furthermore, the Charpy impact and fracture toughness test data for standard and reconstituted specimens have been compared considering the known relationship between the reference temperature T0 and the transition temperature T28J which corresponds to the Charpy energy level of 28 J. Another objective of this study was to compare the RPV metal embrittlement rate for the two reactor pressure vessels using surveillance test data from standard and reconstituted fracture toughness specimens. The analysis has shown that test data for the reconstituted specimens is consistent with the test data for the standard specimens with regard to the embrittlement rate.

A Method to Quantify Thermal Aging Effect on Fracture Toughness of Cast Stainless Steels Using Small Punch Test

2014 ◽  
Author(s):  
Jun-Young Jeon ◽  
Dong-Il Ryu ◽  
Yun-Jae Kim ◽  
Mi-Yeon Lee ◽  
Jin-Weon Kim
Keyword(s):  
Fracture Toughness ◽  
Test Data ◽  
Stainless Steels ◽  
Fracture Strain ◽  
Fracture Toughness Test ◽  
Small Punch ◽  
Fracture Simulation ◽  
Toughness Test ◽  
Axial Fracture ◽  
Strain Model

In this study, a method to predict fracture toughness of aged cast austenitic stainless steels (CASSs) using small punch (SP) test and finite element (FE) analysis is proposed. Grade CF8M is considered and thermally aged up to 5,000 hours at 400°C. SP tests and fracture toughness test using compact tension (C(T)) specimen are conducted with virgin (unaged) and aged CF8M. FE analyses performed in this study use ductile fracture simulation technique with ‘the multi-axial fracture strain model’. The multi-axial fracture strain model for each aged CF8M are determined from SP test data and FE analyses. Fracture toughness of aged CF8M are predicted by conducting fracture toughness test simulations using FE damage analyses. Predicted fracture toughness results are compared with C(T) data to validate the method suggested in this study. The predicted initiation toughness values are predicted well and fracture toughness values are slightly conservative compared to test data.

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