TY - JOUR
T1 - T-stress, mixed-mode stress intensity factors, and crack initiation angles in functionally graded materials
T2 - A unified approach using the interaction integral method
AU - Kim, Jeong Ho
AU - Paulino, Glaucio H.
N1 - Funding Information:
We would like to thank the support from NASA-Ames, Engineering for Complex Systems Program, and the NASA-Ames Chief Engineer (Dr. Tina Panontin) through grant NAG 2-1424. Additional support from the National Science Foundation (NSF) under grant CMS-0115954 (Mechanics & Materials Program) is also appreciated. Any opinions expressed herein are those of the writers and do not necessarily reflect the views of the sponsors.
PY - 2003/3/14
Y1 - 2003/3/14
N2 - For linear elastic functionally graded materials (FGMs), the fracture parameters describing the crack tip fields include not only stress intensity factors (SIFs) but also T-stress (nonsingular stress). These two fracture parameters are important for determining the crack initiation angle under mixed-mode loading conditions in brittle FGMs (e.g. ceramic/ceramic such as TiC/SiC). In this paper, the mixed-mode SIFs and T-stress are evaluated by means of the interaction integral, in the form of an equivalent domain integral, in combination with the finite element method. In order to predict the crack initiation angle in brittle FGMs, this paper makes use of a fracture criterion which incorporates the T-stress effect. This type of criterion involves the mixed-mode SIFs, the T-stress, and a physical length scale rc (representative of the fracture process zone size). Various types of material gradations are considered such as continuum models (e.g. exponentially graded material) and micromechanics models (e.g. self-consistent model). Several examples are given to show the accuracy and efficiency of the interaction integral scheme for evaluating mixed-mode SIFs, T-stress, and crack initiation angle. The techniques developed provide a basic framework for quasi-static crack propagation in FGMs.
AB - For linear elastic functionally graded materials (FGMs), the fracture parameters describing the crack tip fields include not only stress intensity factors (SIFs) but also T-stress (nonsingular stress). These two fracture parameters are important for determining the crack initiation angle under mixed-mode loading conditions in brittle FGMs (e.g. ceramic/ceramic such as TiC/SiC). In this paper, the mixed-mode SIFs and T-stress are evaluated by means of the interaction integral, in the form of an equivalent domain integral, in combination with the finite element method. In order to predict the crack initiation angle in brittle FGMs, this paper makes use of a fracture criterion which incorporates the T-stress effect. This type of criterion involves the mixed-mode SIFs, the T-stress, and a physical length scale rc (representative of the fracture process zone size). Various types of material gradations are considered such as continuum models (e.g. exponentially graded material) and micromechanics models (e.g. self-consistent model). Several examples are given to show the accuracy and efficiency of the interaction integral scheme for evaluating mixed-mode SIFs, T-stress, and crack initiation angle. The techniques developed provide a basic framework for quasi-static crack propagation in FGMs.
KW - Finite element method
KW - Functionally graded material
KW - Interaction integral
KW - Stress intensity factor
KW - T-stress
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U2 - 10.1016/S0045-7825(02)00652-7
DO - 10.1016/S0045-7825(02)00652-7
M3 - Article
AN - SCOPUS:0037436532
SN - 0045-7825
VL - 192
SP - 1463
EP - 1494
JO - Computer Methods in Applied Mechanics and Engineering
JF - Computer Methods in Applied Mechanics and Engineering
IS - 11-12
ER -