Crack Initiation Angles in Functionally Graded Materials under Mixed Mode Loading

2008 ◽  
Author(s):  
Alpay Oral ◽  
Jorge L. Abanto-Bueno ◽  
John Lambros ◽  
Gunay Anlas ◽  
Glaucio H. Paulino ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Functionally Graded Materials ◽  
Mixed Mode ◽  
Functionally Graded ◽  
Mixed Mode Loading ◽  
Graded Materials

Crack Initiation in Functionally Graded Materials Under Mixed Mode Loading: Experiments and Simulations

2008 ◽  
Vol 75 (5) ◽  
Author(s):  
Alpay Oral ◽  
John Lambros ◽  
Gunay Anlas
Keyword(s):  
Crack Initiation ◽  
Tangential Stress ◽  
Functionally Graded Materials ◽  
Mixed Mode ◽  
Process Zone ◽  
Functionally Graded ◽  
Maximum Tangential Stress ◽  
Homogeneous Material ◽  
Mixed Mode Loading ◽  
Graded Materials

In this work, quasistatic crack initiation under mixed mode loading in planar (two-dimensional plane stress) functionally graded materials (FGMs) is studied. The goal of this work is to directly compare experiments and simulations so as to evaluate the applicability of the maximum tangential stress (MTS) criterion in predicting crack kinking in FGMs. Initially, crack initiation in the homogeneous material, which forms the basis of our FGM—polyethylene—is studied. The (generalized) maximum tangential stress is applied through the use of finite elements to determine crack initiation angles in the same graded configurations studied experimentally. Computational results of fracture parameters (stress intensity factors and T-stress), and crack initiation angles are compared to experimental results and good agreement is obtained. It is seen that the MTS criterion is applicable to FGM crack initiation prediction if the inherent material gradient length scale is larger than the fracture process zone.

A New Interaction Integral Method for Mesh-Free Analysis of Cracks in Functionally Graded Materials

2002 ◽  
Author(s):  
B. N. Rao ◽  
S. Rahman
Keyword(s):  
Functionally Graded Materials ◽  
Meshless Method ◽  
Mixed Mode ◽  
Functionally Graded ◽  
Mixed Mode Fracture ◽  
Smooth Functions ◽  
Graded Materials ◽  
Element Free Galerkin ◽  
Mesh Free ◽  
Element Free

This paper presents a Galerkin-based meshless method for calculating stress-intensity factors (SIFs) for a stationary crack in two-dimensional functionally graded materials of arbitrary geometry. The method involves an element-free Galerkin method (EFGM), where the material properties are smooth functions of spatial co-ordinates and two newly developed interaction integrals for mixed-mode fracture analysis. These integrals can also be implemented in conjunction with other numerical methods, such as the finite element method (FEM). Five numerical examples including both mode-I and mixed-mode problems are presented to evaluate the accuracy of SIFs calculated by the proposed EFGM. Comparisons have been made between the SIFs predicted by EFGM and available reference solutions in the literature, generated either analytically or by FEM using various other fracture integrals or analyses. A good agreement is obtained between the results of the proposed meshless method and the reference solutions.

Sign in / Sign up

Export Citation Format

Share Document