Title: Fracture modelling of DP780 sheets using a hybrid experimental-numerical method and two-dimensional digital image correlation

Authors: Keunhwan Pack; Kwanghyun Ahn; Hoon Huh; Yanshan Lou

Addresses: School of Mechanical, Aerospace and Systems Engineering, KAIST, 291 Daehak-ro, Build. N7, Rm. 1203, Yuseong-gu, Daejeon 305-701, Korea ' School of Mechanical, Aerospace and Systems Engineering, KAIST, 291 Daehak-ro, Build. N7, Rm. 1203, Yuseong-gu, Daejeon 305-701, Korea ' School of Mechanical, Aerospace and Systems Engineering, KAIST, 291 Daehak-ro, Build. N7, Rm. 1203, Yuseong-gu, Daejeon 305-701, Korea ' School of Mechanical, Aerospace and Systems Engineering, KAIST, 291 Daehak-ro, Build. N7, Rm. 1203, Yuseong-gu, Daejeon 305-701, Korea

Abstract: This paper is concerned with the construction of fracture envelopes of DP780 sheets using two methods: a hybrid experimental-numerical method; two-dimensional digital image correlation (2D-DIC). For the hybrid method, four types of ductile fracture tests were carried out covering a wide range of stress states on specimens: with a central hole; two symmetric circular notches; flat grooved; and diagonally double-notched. Based on the fracture strain and loading paths identified with finite element simulation, a fracture envelope was obtained by employing the three-parameter modified Mohr-Coulomb fracture model. In addition, the fracture surface strain was directly measured using 2D-DIC. Loading histories of each test were extracted from a surface element of a three dimensional finite element model. The comparison of fracture envelopes constructed by the two methods reveals that there is little difference. Thus, it can be concluded that 2D-DIC is applicable to fracture modelling of DP780 sheets despite the assumption of the plane stress condition even after necking.

Keywords: ductile fracture; digital image correlation; DIC; fracture locus; fracture forming limit diagrams; stress; necking; fracture strain; finite element analysis; FEA; simulation; fracture modelling.

DOI: 10.1504/IJMPT.2014.059029

International Journal of Materials and Product Technology, 2014 Vol.48 No.1/2/3/4, pp.34 - 46

Received: 17 Jan 2013
Accepted: 20 Aug 2013
Published online: 30 May 2014 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article