Elastic-Damaging Plasticity Model for Ductile Fracture

This study is directed toward the development of a simple material model that can characterize ductile fracture in ferritic steels and that can be used in practical engineering problems. Ductile fracture occurs by a sequential process of nucleation, growth and coalescence of microvoids or microcracks. However, the model uses a continuum approach that can capture the global effect of ductile fracture behavior. It consists of two uncoupled material models; an elastic-damaging model that employs continuum damage mechanics and a von Mises plasticity model. The elastic-damaging model is based on the assumption that damage occurs due only to hydrostatic tension, and this, combined with the von Mises plasticity model, allows a simple formulation of the proposed model. Parameters required by the proposed model are determined by calibrating against experimental data for a specific material. The parameters for the elastic-damaging model depend on the spatial distribution of hydrostatic tension, and are determined by a calibration procedure that utilizes axisymmetric notched specimens. The proposed model is implemented in ABAQUS using a user-defined subroutine, i.e. UMAT. Applications to four-point plane strain bending specimens with a key hole notch and to double-tee circular hollow section tubular joints are presented. The proposed model appears to be capable of simulating, with reasonable accuracy, the failure of metal structures due to ductile fracture.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Civil Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2015

Author dc:creator

• Ha, Christopher Chul

Contributors dc:contributor

• Pecknold, David A.

• Engineering, Metallurgy

Language dc:language

eng

Identifier

(MiAaPQ)AAI9996636

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/83524