On fracture behaviour of inhomogeneous materials - a case study for elastically inhomogeneous bimaterials

Otmar Kolednik (Author), Jožef Predan (Author), G.X. Shan (Author), N.K. Simha (Author), Franz Dieter Fischer (Author)

Abstract

This paper presents a case study, examining the influence of a sharp bimaterial interface on the effective crack driving force in a fracture mechanics specimen. The inhomogeneity of the elastic modulus in linear elasticand non-hardening and hardening elastic-plastic bimaterials is considered. The interface is perpendicular to the crack plane. The material properties and the distance between the crack tip and the interface are systematically varied. The effect of the material inhomogeneity is captured in form of a quantity called "material inhomogeneity term",▫$C_inh$▫. This term can be evaluated either by a simple post-processing procedure, following a conventional finite element stress analysis, or by computing the J-integral along a contour around the interface, ▫$J_int$▫. The effective crack driving force,▫$J_tip$▫, can be determined as the sum of ▫$C_inh$▫ and the nominally applied far-field crack driving force, ▫$J_far$▫. The results show that ▫$C_inh$▫ can be accurately determined by both methods even in cases where ▫$J_tip$▫-values are inaccurate. When a crack approaches a stiff/compliant interface,▫$C_inh$▫ is positive and ▫$J_tip$▫ becomes larger than ▫$J-far$▫. A compliant/stiff transition leads to a negative ▫$C_inh$▫, and ▫J_tip$▫ becomes smaller than ▫$J_far$▫. The material inhomogeneity term, ▫$C_inh$▫, can have the same order of magnitude as ▫$J_far$▫. Based on the numerical results, the dependencies of ▫$C_inh$▫ on the material parameters and the geometry are derived. Simple expressions are obtained to estimate ▫$C_inh$▫.

Keywords

mehanika konstrukcij;lomna žilavost;nehomogeni materiali;J-integral;gonilna sila razpoke;meja;sila odpora materiala;mechanics of structures;fracture toughness;inhomogeneous materials;crack driving force;interface;material force;

Data

Language:	English
Year of publishing:	2005
Typology:	1.01 - Original Scientific Article
Organization:	UM FS - Faculty of Mechanical Engineering
UDC:	539.3:620.1
COBISS:	9129238
ISSN:	0020-7683
Views:	1176
Downloads:	19
Average score:	0 (0 votes)
Metadata:

Other data

Secondary language:	English
Secondary keywords:	mehanika konstrukcij;lomna žilavost;nehomogeni materiali;J-integral;gonilna sila razpoke;meja;sila odpora materiala;
URN:	URN:SI:UM:
Pages:	str. 605-620
Volume:	ǂVol. ǂ42
Issue:	ǂiss. ǂ2
Chronology:	2005
ID:	8718455