scholarly journals Simulation of ductile crack initiation and propagation by means of a non-local Gurson-model

2013 ◽  
Vol 50 (5) ◽  
pp. 662-671 ◽  
Author(s):  
Geralf Hütter ◽  
Thomas Linse ◽  
Uwe Mühlich ◽  
Meinhard Kuna
Keyword(s):  
Crack Initiation ◽  
Ductile Crack ◽  
Crack Initiation And Propagation ◽  
Gurson Model ◽  
Initiation And Propagation ◽  
Non Local

Crack Initiation and Growth in Bimetallic Girth Welds

2014 ◽  
Author(s):  
Antonio Carlucci ◽  
Nicola Bonora ◽  
Andrew Ruggiero ◽  
Gianluca Iannitti ◽  
Domenico Gentile
Keyword(s):  
Crack Initiation ◽  
Damage Mechanics ◽  
Damage Model ◽  
Mouth Opening ◽  
Crack Mouth Opening Displacement ◽  
Model Parameters ◽  
Ductile Crack ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation ◽  
Girth Welds

Bimetallic girth welds are characteristics of clad pipe technology. When dealing with propagation issues, fracture mechanics concepts usually are no longer applicable as a result of the extensive and non-homogeneous plastic deformation along bi-material interface that occur at the crack tip even below design allowables. In this study, ductile crack initiation and propagation in bi-material girth welds was investigated using a Continuum Damage Mechanics (CDM) model proposed by Bonora [1]. For the base, weld and clad metal, ductile damage model parameters have been determined by means of inverse calibration technique using fracture data obtained on smooth and round notched tensile bar specimens. Firstly, the damage model was validated predicting ductile crack growth occurring in single end notch (SEN(T)) geometry sample comparing the applied load vs crack mouth opening displacement with experimental measurements. Successively, the model was used to investigate ductile crack initiation and propagation for under clad circumferential weld crack under remote tension.

Numerical Analysis of Influence of the Martensite Volume Fraction on Dp Steels Behavior During Plastic Deformation / Analiza Numeryczna Wpływu Ułamka Objetosci Martenzytu Na Zachowanie Stali Dp Podczas Odkształcenia Plastycznego

2013 ◽  
Vol 58 (1) ◽  
pp. 211-215 ◽  
Author(s):  
K. Perzynski ◽  
Ł. Madej
Keyword(s):  
Crack Initiation ◽  
Volume Fraction ◽  
Failure Behavior ◽  
Ductile Crack ◽  
Crack Initiation And Propagation ◽  
Martensite Volume Fraction ◽  
Propagation Behavior ◽  
Initiation And Propagation ◽  
Digital Material ◽  
Dp Steels

Development of a comprehensive fracture model, which takes into account crack initiation and propagation behavior at the microscale level in the Dual Phase (DP) steels is presented in the present paper. At this stage of the research Authors proposed a numerical model, which takes into account ductile crack initiation and propagation through the ferrite phase. Developed model is based on digital material representation (DMR) of DP microstructure, which takes opportunity for modeling crack phenomena in an explicit manner. Proposed model of ductile crack behavior in the ferritic phase is based on the Johnson-Cook model. Particular attention is put on investigation of influence of martensite volume fraction in microstructure on failure behavior. Obtained results for two significantly different martensite volume fractions in the investigated microstructure are presented in this work

Crack Initiation and Propagation Clad Pipe Girth Weld Flaws

2014 ◽  
Author(s):  
Antonio Carlucci ◽  
Nicola Bonora ◽  
Andrew Ruggiero ◽  
Gianluca Iannitti ◽  
Gabriel Testa
Keyword(s):  
Crack Initiation ◽  
Large Scale ◽  
Damage Mechanics ◽  
High Fracture Toughness ◽  
Model Parameters ◽  
Equivalent Material ◽  
Ductile Crack ◽  
Crack Initiation And Propagation ◽  
Brittle Ductile Transition ◽  
Initiation And Propagation

At present, design standards and prescriptions do not provide specific design routes to perform engineering criticality assessment (ECA) of bimetallic girth welds. Although the authors has shown the possibility to implement ECA in accordance with available prescriptions of such flawed weld joint following the equivalent material method (EMM), when dealing with ductile crack initiation and propagation — as a result of the large scale yielding occurring at the crack tip for high fracture toughness material operating in the brittle-ductile transition region — fracture mechanics concepts such as JIc or critical CTOD may breakdown. In this work, the possibility to accurately determine the condition for ductile crack growth initiation and propagation in bi-metallic girth weld flaws using continuum damage mechanics is shown. Here, the base metal as well as the clad and the weld metal have been characterized to determine damage model parameters. Successively, the geometry transferability of model parameters has been validated. Finally, the model has been used to predict crack initiation for two bi-material interface circumferential crack configurations.

Ductile crack initiation and propagation assessed via in situ synchrotron radiation-computed laminography

2011 ◽  
Vol 65 (11) ◽  
pp. 1010-1013 ◽  
Author(s):  
T.F. Morgeneyer ◽  
L. Helfen ◽  
I. Sinclair ◽  
H. Proudhon ◽  
F. Xu ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Crack Initiation ◽  
Ductile Crack ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation ◽  
Computed Laminography

Modeling Crack Initiation and Propagation in Nickel Base Superalloys

2007 ◽  
Vol 348-349 ◽  
pp. 53-56
Author(s):  
Alexander M. Korsunsky ◽  
Xu Song ◽  
Jonathan Belnoue ◽  
Leo D.G. Prakash ◽  
Daniele Dini ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Guide Vane ◽  
Turbine Blades ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation ◽  
Non Local ◽  
Nickel Base Superalloys ◽  
High Temperature Components ◽  
Materials Used ◽  
Nickel Base

Nickel base superalloys are the primary class of materials used in the manufacture of high temperature components for gas turbine aeroengines, including combustion casings and liners, guide vane and turbine blades and discs, etc. These components are subjected to complex cyclic loading induced by the combination of mechanical loading, changing temperatures and thermal gradients, inducing plastic deformation and creep, that ultimately may lead to crack initiation and propagation. The purpose of the present paper is to provide a necessarily brief overview of recent modeling activities in this field, including polycrystalline crystal plasticity modeling for the study of crack initiation, coupled non-local damage-plasticity modeling for crack initiation and propagation studies, and the incorporation of time and environment dependent processes (creep and oxidation) in the predictive modeling of fatigue crack growth rates in nickel base superalloys.

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