SEDL / STP / STP1417-EB / STP11087S



Analytical and Experimental Study of Fracture in Bend Specimens Subjected to Local Compression

Meith, WA
Graduate student and Assistant Professor, University of California, Davis,CA

Hill, MR
Graduate student and Assistant Professor, University of California, Davis,CA

Panontin, TL
Chief Engineer, NASA Ames Research Center, Moffett Field,CA


Pages: 17    Published: Jan 2003


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Source: STP1417-EB


Abstract

This study presents finite element simulations and fracture predictions for experimental conditions in a recent ASTM round-robin program on weld fracture toughness. The simulations include the effects of weld residual stress and residual stress alteration due to local compression of notched SE(B) specimens. Simulations are performed for a variety of material models and local compression details. Fracture is predicted using crack-tip stress and strain as inputs to both a local and a global prediction scheme. The local prediction is based on the RKR micromechanical model. The global prediction is based on obtaining a critical value of the J-integral, computed using a modified domain integral. Results predict that fracture toughness in the round robin was markedly reduced by local compression of the specimens. The amount of the reduction depends on the position of the compression platen relative to the notch-tip, but is largely independent of the amount of local compression applied. Available data from the round robin do not completely confirm the prediction results, but some of these data may have been influenced by warm pre-stressing during fatigue pre-cracking.


Keywords:
local compression, weld metal, residual stress, fracture toughness

Paper ID: STP11087S
Committee/Subcommittee: E08.07
DOI: 10.1520/STP11087S
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