Hybrid experimental-numerical determination of the loading path to fracture in TRIP780 sheets subjected to multi-axial loading

The development of ductile fracture models of metals requires reliable measurements of the stress and strain histories up to the onset of fracture in multi-axial experiments. In the present work, a hybrid experimental-numerical approach is taken to determine the loading path in various fracture experiments on TRIP780 steel sheets. In most mechanical experiments on sheet metal, the localization of plastic deformation precedes the onset of fracture. After the beginning of necking, the stress fields within the specimen gage section become non-uniform and of three dimensional nature. Consequently, the stress history prior to fracture can no longer be estimated based on the force history measurements using simple analytical formulas. A detailed finite element analysis of each experiment is required to identify the local stress and strain fields. The results of the hybrid experimental-numerical analysis of a fracture experiment depend strongly on the chosen constitutive model. Here, an extensive bi-axial experimental program comprising more than 20 distinct loading conditions is performed to characterize the monotonic large deformation behavior of the TRIP780 steel. It is found that an anisotropic quadratic yield function along with a non-associated flow rule can accurately describe the inelastic behavior of the TRIP material.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2010

Author dc:creator

• Dunand, Matthieu

Advisor dc:contributor.advisor

• Dirk Mohr and Tomasz Wierzbicki.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/57573

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/57573