ISSN: 1546-962X
CODEN: JAIOAD
Published Online: 14 January 2010
Page Count: 11

A Weibull Stress Model to Predict Effects of Weld Strength Mismatch on Cleavage Fracture Toughness

Ruggieri, Claudio
Dept. of Naval Architecture and Ocean Engineering, Univ. of São Paulo, São Paulo, São Paulo

(Received 15 May 2009; accepted 25 November 2009)

Abstract

This work describes the development of a toughness scaling methodology incorporating the effects of weld strength mismatch on crack-tip driving forces. The approach adopts a nondimensional Weibull stress, σ¯w, as a the near-tip driving force to correlate cleavage fracture across cracked weld configurations with different mismatch conditions even though the loading parameter (measured by J or crack-tip opening displacement) may vary widely due to mismatch and constraint variations. Application of the procedure to predict the failure strain for an overmatch girth weld made of an API X80 pipeline steel demonstrates the effectiveness of the micromechanics approach. Overall, the results lend strong support to use a Weibull stress based procedure in defect assessments of structural welds.

Keywords:
cleavage fracture, weld strength mismatch, Weibull stress, local approach, toughness scaling model

Paper ID: JAI102508
DOI: 10.1520/JAI102508
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