Mode II Brittle Fracture Assessment of Key-Hole Notches by Means of the Local Energy

2014 ◽  
Vol 44 (3) ◽  
pp. 20140295 ◽  
Author(s):  
A. R. Torabi ◽  
A. Campagnolo ◽  
F. Berto
Keyword(s):  
Brittle Fracture ◽  
Mode Ii ◽  
Local Energy ◽  
Fracture Assessment

Mode II Brittle Fracture Assessment Using ASFPB Specimen

2009 ◽  
Vol 159 (2) ◽  
pp. 241-246 ◽  
Author(s):  
M. R. M. Aliha ◽  
M. R. Ayatollahi ◽  
B. Kharazi
Keyword(s):  
Brittle Fracture ◽  
Mode Ii ◽  
Fracture Assessment

Mode II brittle fracture assessment using an energy based criterion

2017 ◽  
Vol 20 (2) ◽  
pp. 142-148 ◽  
Author(s):  
M. Rashidi Moghaddam ◽  
M. R. Ayatollahi ◽  
S. M. J. Razavi ◽  
F. Berto
Keyword(s):  
Brittle Fracture ◽  
Mode Ii ◽  
Fracture Assessment

Lower Strength Steel Brittle Fracture Assessment

1974 ◽  
Vol 100 (5) ◽  
pp. 983-999
Author(s):  
Mohammed H. Magued ◽  
D. J. Laurie Kennedy
Keyword(s):  
Brittle Fracture ◽  
Lower Strength ◽  
Fracture Assessment

Computational Methods to Support Brittle Fracture Assessment of PSVs Involving Autorefrigeration

2015 ◽  
Author(s):  
Kannan Subramanian ◽  
Jorge Penso ◽  
Harbi Pordal
Keyword(s):  
Brittle Fracture ◽  
Computational Methods ◽  
Cost Effective ◽  
Liquid Hydrocarbon ◽  
Computational Method ◽  
Metal Temperature ◽  
Relief Valve ◽  
Sensitivity Studies ◽  
Fracture Assessment ◽  
Cfd Method

Pressure safety relief valve (PSV) operation generally leads to cooling of the valve itself and the piping connected to the PSV. The temperatures may reach values below the minimum design metal temperature (MDMT) of the valve, and therefore the valve needs to be assessed for brittle fracture susceptibility. Simplistic determination of the minimum metal temperature in the valve may disqualify these valves during the brittle fracture assessments (BFA). Replacement may be time consuming and may not be cost effective. In such circumstances, a sophisticated and more representative BFA approach involving the use of computational fluid dynamics (CFD) followed by finite element method (FEM) based stress analysis which may be further followed by fracture mechanics can be adopted based on the concepts defined in ASME/API 579. The accuracy of the BFA depends on the accuracy of each of the computational method involved in the assessment. Among all the computational methods, CFD poses significant challenge. The low temperature may have been caused due to Joule-Thompson effect or auto-refrigeration. While Joule-Thompson effect can be best captured with easy to implement and robust CFD methods, auto-refrigeration involving adiabatic flashing which causes additional complexity and requires multiple sensitivity studies performed to determine the accuracy of the CFD approach. In this paper, an overview of the computational methods used in the brittle fracture assessment of PSVs is presented. Specific CFD method details are provided for PSV involving the flashing of liquid hydrocarbon to vapor is presented in the form of a case study derived from downstream industry application.

Brittle Fracture Assessment and Failure Assessment Diagrams

2021 ◽  
pp. 1-8
Author(s):  
Brian Macejko
Keyword(s):  
Fracture Mechanics ◽  
Brittle Fracture ◽  
Flaw Size ◽  
Process Equipment ◽  
Reliable Prediction ◽  
Fracture Failure ◽  
Failure Assessment ◽  
Fracture Assessment ◽  
Assessment Procedures

Abstract A detailed fracture mechanics evaluation is the most accurate and reliable prediction of process equipment susceptibility to brittle fracture. This article provides an overview and discussion on brittle fracture. The discussion covers the purpose for evaluating, provides a brief summary of historical failures that were found to be a result of brittle fracture, and describes key components that drive susceptibility to a brittle fracture failure, namely stress, toughness/temperature, and flaw size. It also presents industry codes and standards that assess susceptibility to brittle fracture. Additionally, a series of case study examples are presented that demonstrate assessment procedures used to mitigate the risk of brittle fracture in process equipment.

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.

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