applied fracture mechanics

Evaluating the Integrity of Pressure Pipelines by Fracture Mechanics 285Several relations have been reported for determining the Folias correction factor. Thefollowing are the most frequently used at the present time:The Folias relation (Folias, 1970):The Erdogan et al. relation (Erdogan et al., 1977):2 4M 1 1.255 0.0135(1)T2where 4 121 M 0.6 0.5 0.4exp( 1.25 ) for 5M TT 0.5 1.761 1.9 for 5(2)with ν denoting Poisson´s ratioThe following relation is the simplest:MTHowever, its validity is limited by the value λ