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Title: ON SOME BENCHMARK RESULTS FOR THE INTERACTION OF A CRACK WITH A CIRCULAR INCLUSION

Abstract

Stress intensity factor calculations for crack-inclusion interaction problems are presented. The problems considered include the benchmark problems first discussed by Helsing and Jonsson, and subsequently by Wang, Mogilevskaya and Crouch. The numerical results are obtained using the symmetric-Galerkin boundary element method in conjunction with an improved quarter-point element for evaluating the stress intensity factors by means of the displacement correlation technique. The converged results confirm the accuracy of the previous simulations, and demonstrate that accurate solutions for these interaction problems can be obtained with numerical methods that are applicable in three dimensions.

Authors:
 [1];  [1];  [1]
  1. ORNL
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
979073
DOE Contract Number:
DE-AC05-00OR22725
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Mechanics; Journal Volume: 74
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ACCURACY; BENCHMARKS; BOUNDARY ELEMENT METHOD; DIMENSIONS; STRESS INTENSITY FACTORS

Citation Formats

Phan, Anh-Vu, Gray, Leonard J, and Kaplan, Ted. ON SOME BENCHMARK RESULTS FOR THE INTERACTION OF A CRACK WITH A CIRCULAR INCLUSION. United States: N. p., 2007. Web. doi:10.1115/1.2722773.
Phan, Anh-Vu, Gray, Leonard J, & Kaplan, Ted. ON SOME BENCHMARK RESULTS FOR THE INTERACTION OF A CRACK WITH A CIRCULAR INCLUSION. United States. doi:10.1115/1.2722773.
Phan, Anh-Vu, Gray, Leonard J, and Kaplan, Ted. Mon . "ON SOME BENCHMARK RESULTS FOR THE INTERACTION OF A CRACK WITH A CIRCULAR INCLUSION". United States. doi:10.1115/1.2722773.
@article{osti_979073,
title = {ON SOME BENCHMARK RESULTS FOR THE INTERACTION OF A CRACK WITH A CIRCULAR INCLUSION},
author = {Phan, Anh-Vu and Gray, Leonard J and Kaplan, Ted},
abstractNote = {Stress intensity factor calculations for crack-inclusion interaction problems are presented. The problems considered include the benchmark problems first discussed by Helsing and Jonsson, and subsequently by Wang, Mogilevskaya and Crouch. The numerical results are obtained using the symmetric-Galerkin boundary element method in conjunction with an improved quarter-point element for evaluating the stress intensity factors by means of the displacement correlation technique. The converged results confirm the accuracy of the previous simulations, and demonstrate that accurate solutions for these interaction problems can be obtained with numerical methods that are applicable in three dimensions.},
doi = {10.1115/1.2722773},
journal = {Journal of Applied Mechanics},
number = ,
volume = 74,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
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  • Crack initiation at inclusions is a dominant, unavoidable and life-limiting failure mechanism of important structural materials. Fatigue progresses in a complex manner to find the ‘weakest link’ in the microstructure, leading to crack nucleation. In this study, fully 3-D characterization methods using high-energy synchrotron x-rays are combined with in-situ mechanical testing to study the crack initiation mechanism in a Ni-based superalloy specimen. The specimen was produced via powder metallurgy and seeded with a non-metallic inclusion. Two x-ray techniques were employed: absorption contrast computed micro-tomography (μ-CT) to determine the morphology of the inclusion and its location in the gauge section ofmore » the specimen; and far-field high-energy diffraction microscopy (FF-HEDM) to resolve the centroids, average orientations, and lattice strains of the individual grains comprising the microstructure surrounding the inclusion. Sequential μ-CT and FF-HEDM scans were carried out at both peak and zero applied stress following schedules of cyclic deformation. The µ-CT data showed the onset and location of crack initiation, and the FF-HEDM data provided temporal and spatial evolution of the intergranular strains. Strain partitioning and the associated stress heterogeneities that develop are shown to stabilize within a few loading cycles. Elasto-viscoplastic fast Fourier transform simulations were utilized to supplement interpretation of the experimental stress distributions and compared with the experimental stress distributions. In conclusion, appropriate conditions for crack nucleation in the form of stress gradients were demonstrated and created by virtue of the inclusion, specifically the residual stress state and local bonding state at the inclusion-matrix interface.« less