Aleatory uncertainty and scale effects in computational damage models for failure and fragmentation / RB Leavy, OE Strack, RM Brannon.

Format:

Book

Government document

Author/Creator:

Leavy, R. B., author.

Strack, O. E., author.

Brannon, R. M., author.

Contributor:

U.S. Army Research Laboratory, issuing body.

Language:

English

Subjects (All):

Fracture mechanics.

Algorithms.

Strains and stresses.

algorithms.

Medical Subjects:

Algorithms.

Genre:

Text

Physical Description:

1 online resource (ii, 30 pages) : color illustrations

Place of Publication:

Aberdeen Proving Ground, MD : Army Research Laboratory, 2014.

Language Note:

English

Summary:

Stress concentrations near grain boundaries, precipitates, and similar micro-heterogeneities nucleate instabilities leading to macroscale fracture. As it is not practical to model each flaw explicitly, their ensemble effect is modeled statistically. Accounting for this aleatory uncertainty requires smaller specimens (e.g., small finite elements) to have generally higher and more variable strengths, which is necessary for the initial failure probability of a finite domain to be unaffected by its discretization into elements. Localization itself, which might be attributed to constitutive instability, requires realistic numerical perturbations to predict bifurcations such as radial cracking in axisymmetric problems. These perturbations, stemming from microscale heterogeneity, are incorporated in simulations by imposing statistical spatial variability in the parameters of an otherwise conventional (deterministic and scale-independent) damage model. This approach is attractive for its algorithmic simplicity and straightforward calibration from standard strength tests. In addition, it results in virtually no loss of efficiency or robustness relative to deterministic models and accommodates general three dimensional loading. Despite these advantages, some significant challenges remain and are discussed. However, it is demonstrated that including aleatory uncertainty with associated scale effects significantly improves predictiveness on large-scale computational domains, where it is impractical to resolve each crack or localization zone.

The original document contains color images. Prepared in collaboration with Sandia National Laboratories, Computational Shock and Multiphysics, Albuquerque, NM and the University of Utah, Mechanical Engineering, Salt Lake City, UT. Published in the Int. J. Numer. Meth. Engng., 2014. Sponsored in part by DoE.

Notes:

"September 2014."

Offprint from: International journal for numerical methods in engineering, 2014.

"ARL-RP-0497."

Includes bibliographical references (pages 25-28).

Approved for public release; distribution is unlimited.

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Description based on online resource; title from PDF title page (ARL website, viewed Aug. 22, 2018).

OCLC:

913591427

Access Restriction:

Open access content Open access content