Publication: Validating Theories for Brittle Damage

R.M. Brannon, J.M. Wells, and O.E. Strack

Realistic-looking, uneven damage zones in Brazilian simulations compare favorably with laboratory data for observable damage

Validating simulated predictions of internal damage within armor ceramics is preferable to simply assessing a models ability to predict penetration depth, especially if one hopes to perform subsequent ‘‘second strike’’ analyses. We present the results of a study in which crack networks are seeded by using a statistically perturbed strength, the median of which is inherited from a deterministic ‘‘smeared damage’’ model, with adjustments to reflect experimentally established size effects. This minor alteration of an otherwise conventional damage model noticeably mitigates mesh dependencies and, at virtually no computational cost, produces far more realistic cracking patterns that are well suited for validation against X-ray computed tomography (XCT) images of internal damage patterns. For Brazilian, spall, and indentation tests, simulations share qualitative features with externally visible damage. However, the need for more stringent quantitative validation, software quality testing, and subsurface XCT validation, is emphasized.

Available Online:

http://www.mech.utah.edu/~brannon/pubs/7-2007ValidatingTheoriesForBrittleFailure11661_2007_9310_OnlinePDF.pdf

http://www.springerlink.com/content/p4314137017u7t32/

 

 

 

 

Tags: Weibull, fracture, damage, X-ray computed tomography (XCT), uncertainty, statistics, verification, validation

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