Gurson model parameters for ductile fracture simulation in ASTM A992 steels

2013 ◽  
Vol 37 (2) ◽  
pp. 171-183 ◽  
Author(s):  
R. Kiran ◽  
K. Khandelwal
2021 ◽  
Vol 11 (9) ◽  
pp. 3774
Author(s):  
Sung-Ju Park ◽  
Kookhyun Kim

The ductile fracture of thin-shell structures was studied here using a localized necking model. The punching experiments for unstiffened and stiffened panels were compared with numerical predictions using a combined ductile fracture and localized necking model using shell elements. The plasticity and fracture model parameters of JIS G3131 SPHC steel were identified by performing calibration experiments on standard flat bars, notched tension, central hole tension, plane strain tension, and shear specimens. The plasticity beyond the onset of necking was modeled using the Swift hardening law. The damage indicator framework with a combined Hosford–Coulomb fracture model and the domain of shell-to-solid equivalence (DSSE) were adopted to characterize the fracture initiation. The model parameters were calibrated based on the loading paths to fracture initiation, which were extracted from a non-linear finite element (FE) analysis. The presented HC–DSSE model was validated using punch tests and was able to predict fracture initiation with good accuracy.


2021 ◽  
Vol 11 (12) ◽  
pp. 5392
Author(s):  
Yonghyun Cho ◽  
Changkye Lee ◽  
Jurng-Jae Yee ◽  
Dong-Keon Kim

A series of earthquake events give impetus to research on the ductile fracture behavior of steel materials. In the last decades, many fracture models have been developed and utilized in the mechanical or aerospace engineering. Nevertheless, very little application to structural members used in the construction industry has been made due to the lack of a suitable model for the fracture behavior of constructional steel. This paper presents the experimental and finite element (FE) technique to predict ductile fracture in mild carbon structural steel (SS275) sheets, which has been widely used in building structures. The post-necking true stress–strain responses were successfully estimated using the weighted-average method. The Bao and Wierzbicki (BW) model, which requires only two model parameters, was selected for the identification of fracture locus. Each model parameter was calibrated from uniaxial tension and in-plane shear specimens with the aid of digital image correlation (DIC) and finite element analysis. Fracture simulation was then performed and validated based on the experimental results of the specimens under combined tension and shear stress state.


2009 ◽  
Vol 65 ◽  
pp. 19-31
Author(s):  
Ruben Cuamatzi-Melendez ◽  
J.R. Yates

Little work has been published concerning the transferability of Gurson’s ductile damage model parameters in specimens tested at different strain rates and in the rolling direction of a Grade A ship plate steel. In order to investigate the transferability of the damage model parameters of Gurson’s model, tensile specimens with different constraint level and impact Charpy specimens were simulated to investigate the effect of the strain rate on the damage model parameters of Gurson model. The simulations were performed with the finite element program ABAQUS Explicit [1]. ABAQUS Explicit is ideally suited for the solution of complex nonlinear dynamic and quasi–static problems [2], especially those involving impact and other highly discontinuous events. ABAQUS Explicit supports not only stress–displacement analyses but also fully coupled transient dynamic temperature, displacement, acoustic and coupled acoustic–structural analyses. This makes the program very suitable for modelling fracture initiation and propagation. In ABAQUS Explicit, the element deletion technique is provided, so the damaged or dead elements are removed from the analysis once the failure criterion is locally reached. This simulates crack growth through the microstructure. It was found that the variation of the strain rate affects slightly the value of the damage model parameters of Gurson model.


Author(s):  
Claudio Ruggieri ◽  
Fernando F. Santos ◽  
Mitsuru Ohata ◽  
Masao Toyoda

This study explores the capabilities of a computational cell framework into a 3-D setting to model ductile fracture behavior in tensile specimens and damaged pipelines. The cell methodology provides a convenient approach for ductile crack extension suitable for large scale numerical analyses which includes a damage criterion and a microstructural length scale over which damage occurs. Laboratory testing of a high strength structural steel provides the experimental stress-strain data for round bar and circumferentially notched tensile specimens to calibrate the cell model parameters for the material. The present work applies the cell methodology using two damage criterion to describe ductile fracture in tensile specimens: (1) the Gurson-Tvergaard (GT) constitutive model for the softening of material and (2) the stress-modified, critical strain (SMCS) criterion for void coalescence. These damage criteria are then applied to predict ductile cracking for a pipe specimen tested under cycling bend loading. While the methodology still appears to have limited applicability to predict ductile cracking behavior in pipe specimens, the cell model predictions of the ductile response for the tensile specimens show good agreemeent with experimental measurements.


2017 ◽  
Vol 114 ◽  
pp. 279-292 ◽  
Author(s):  
Yangjian Xu ◽  
Shuai Zhao ◽  
Guohui Jin ◽  
Xiaogui Wang ◽  
Lihua Liang

Author(s):  
Youn-Young Jang ◽  
Ji-Hee Moon ◽  
Nam-Su Huh ◽  
Ki-Seok Kim ◽  
Woo-Yeon Cho ◽  
...  

Abstract This paper is aimed to characterize ductile and cleavage fracture behavior of API X70 pipeline steel and investigate applicability of a micro-damage mechanics model to simulate static and dynamic crack propagation of single-edge notched tension (SENT) and drop-weight tear test (DWTT) specimens, as well as a local approach to describe cleavage fracture behavior. Gurson-Tvergaard-Needleman (GTN) model was applied to simulate ductile fracture behavior of SENT and DWTT specimens, where GTN model has been widely known for well-established model to characterize micro-damage process of void nucleation, growth and coalescence. As for a local approach, Beremin model was considered to estimate probability of cleavage fracture. In this regard, this study was especially focused on abnormal fracture appearance of DWTT specimen. In the present study, firstly, experiment data from tensile specimen test was used to obtain plastic flow curve (i.e. stress and strain curve). And load-CMOD and J-integral/CTOD resistance curves obtained from SENT test were used to characterize static ductile fracture and calibrate GTN model parameters for X70 pipeline steel. And the calibrated GTN model parameters were verified by comparing experiment data from DWTT test such as load-displacement and crack length-time curves with those from FE analysis. To accommodate dynamic effect on material properties, rate-dependent stress-strain curves were considered in FE analyses. To describe cleavage fracture, the Weibull stress was calculated from FE analyses of DWTT and Weibull parameters were calibrated by comparing with probability distribution of cleavage fracture from experiment data of DWTT specimen. Using Weibull parameters, the whole of cleavage fracture probability can be estimated as ductile shear area of DWTT specimen increases.


Author(s):  
Tobias Bolinder ◽  
Dominique Moinereau ◽  
Patrick Le Delliou ◽  
Anna Dahl ◽  
Jacques Besson

Abstract This paper will assess the capability of the shear modified Gurson model developed by Nahshon and Hutchinson which is used by Kiwa Inspecta within the ATLAS+ project. This is done by comparison to experimental results from SENT fracture tests performed by EDF and ARMINES. The procedure for parameter identification for the standard and shear modified Gurson model is also summarized. The work presented in this paper is part of Work Package 3 within the ATLAS+ project. WP3 focus mainly on ductile tearing predictions for large defects in components. Models exists to accurately predict ductile tearing and to consider phenomena such as stress triaxiality effects. These advanced models include local approach coupled models or advanced energetic approaches. However, there is a need to validate these models for use in industrial applications. This will be done within the ATLAS+ project by predicting the results of the large scale component tests where input to the models are given from small size laboratory specimens. Within the paper a description of the shear modified Gurson model is given, as developed by Nashson and Hutchinson [1]. Furthermore, the procedure in determining the material model parameters is discussed. To determine the material parameters for the shear modified Gurson model a uniaxial tensile test, a fracture test and shear tests are used. The material that is used is the ferritic steel WB 36 (15 NiCuMoNb 5) which will be used for the large scale component tests within the ATLAS+ project. The procedure is also evaluated by comparing predictions done with the shear modified Gurson model to experimental results from SENT specimens performed by EDF and ARMINES. A comparison of the capability in predicting the ductile tearing in the SENT experiments between the standard Gurson model and the shear modified Gurson model is also presented within the paper.


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