A damage model for ductile crack initiation and propagation

2011 ◽  
Vol 47 (6) ◽  
pp. 641-656 ◽  
Author(s):  
P. Areias ◽  
N. Van Goethem ◽  
E. B. Pires
Keyword(s):  
Crack Initiation ◽  
Damage Model ◽  
Ductile Crack ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation

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 When dealing with propagation issues, fracture mechanics concepts usually are no longer applicable as a result of the extensive and non-homogeneous plastic deformation along bi-material interface that occur at the crack tip even below design allowables.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

scholarly journals Numerical modeling of crack initiation and propagation processes in various specimen’s types using the GTN material damage model

2021 ◽  
Vol 5 (1) ◽  
pp. 49-56
Author(s):  
Andrew Kravchuk ◽  
Eugene Kondriakov ◽  
Valery Kharchenko
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modeling ◽  
Crack Initiation ◽  
Damage Model ◽  
Material Damage ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation

Problematic. A combination of experimental and computational methods for studying the processes of crack initiation and propagation in various specimen’s types is used to determine the mechanical properties of materials, as well as to improve the accuracy of assessing the strength and durability of structural elements. Research objective. Determination of the parameters of the Gurson-Tvergaard-Needleman (GTN) material damage model based on the numerical modeling results of various specimen’s types under various types of loading for steel 22K using the finite element method. Realization technique. Using the finite element method, numerical modeling of the processes of cracks nucleation and propagation in cylindrical specimens under uniaxial tension, in Charpy specimens under dynamic loading, and also in CT specimens under quasi-static loading was carried out for steel 22K using the GTN material damage model. The results of research. By comparing the experimental and numerical results, the full set of GTN material model parameters for steel 22K was determined. The stress state in the crack tip area and the kinetics of its propagation in the material of various specimen’s types under static and dynamic loading were estimated. Conclusions. The GTN material damage model with the parameter values determined from experiments, can be used for numerical simulation of the processes of crack initiation and propagation both in specimens of various types under various loading types, and in structural elements.

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
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