Simulation of ductile fracture of structural steels with void growth model and a continuum damage criterion based on it

The aim of this study involved evaluating and predicting forming limit curves of boron steel 22MnB5 sheet at elevated temperatures. A finite-element method simulation was adopted based on ductile fracture criteria and simple experiments at elevated temperatures. First, tensile experimental data and ductile fracture criterions of Johnson–Cook and ductile void growth models were input to ABAQUS/Explicit software to predict and compare the same with fracture occurrence in experiments performed via Hecker’s punch stretching tests at room temperature. Subsequently, punch stretching test data at room temperature were added to correct the fracture strain locus in the space of the stress triaxiality and the equivalent strain following the ductile void growth model. After confirming the accuracy of the forming limit curve prediction at room temperature, fracture strain loci at high temperatures using ductile void growth model were determined based on the average ratio between the fracture equivalent plastic strains at room temperature as well as higher temperatures. Finally, Hecker’s punch stretching tests were numerically simulated to predict forming limit curve(s) of boron steel 22MnB5 sheet at high temperatures.

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Damage mechanical investigations at ductile fracture of free-cutting steels by means of microscopy - void growth and fracture surface topography

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:2001523 ◽

2001 ◽

Vol 11 (PR5) ◽

pp. Pr5-187-Pr5-193 ◽

Cited By ~ 1

Author(s):

R. Schiffmann ◽

U. Wendt ◽

W. Dahl

Keyword(s):

Fracture Surface ◽

Ductile Fracture ◽

Surface Topography ◽

Void Growth

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A Micromechanics Approach to Assess Ductile Crack Initiation in Damaged Pipelines

Fatigue, Fracture, and Damage Analysis ◽

10.1115/pvp2003-1993 ◽

2003 ◽

Author(s):

Claudio Ruggieri ◽

Fernando F. Santos ◽

Mitsuru Ohata ◽

Masao Toyoda

Keyword(s):

Ductile Fracture ◽

Large Scale ◽

Cell Model ◽

High Strength ◽

Void Coalescence ◽

Model Parameters ◽

Ductile Crack ◽

Cracking Behavior ◽

Damage Criterion ◽

Limited Applicability

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.

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