Comportamento à fratura de defeitos circunferenciais em dutos submarinos instalados por bobinamento

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

2009

RESUMO

This study aims to evaluate the limit of the fracture instability for submarine pipelines installed by the Reeling Method, determining the maximum allowable ductile tearing for use in analysis of structural integrity through correlations with SENT specimens (Single Edge Notched Tension). The Standard DNV-RP-F108, which gives guidance to testing and analysis of fracture of pipelines subject to cycles of plastic deformation, recommends 1 mm as threshold for stable crack growth during the installation phase. This limit has been questioned, since it is only a recommendation and an increase in that limit can result in a less restrictive criterion for welding, thus avoiding unnecessary repairs. To check the implications of the use of tearing bigger than that, was conducted an analysis of integrity (ECA - Engineering Critical Assessment) according to the level 3B of BS 7910:2005 with the amendments proposed by DNV. For this level of assessment is needed to evaluate curves of the fracture resistance (J-R) of the material for assessment of the interest points as well the stress-strain curves for the construction of the FAD (Failure Assessment Diagram). Based on the analysis undertaken, it was proposed the use of Jm (J Integral at the maximum loading point) as a criterion for determining the maximum stable crack growth, taking into account the depth of the flaw and the crack growth resistance curve J-R.

ASSUNTO(S)

propagação de trincas : ensaios mecânica da fratura tubulação submarina

ACESSO AO ARTIGO

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