SEDL / STP / STP945-EB / STP23287S

On the Accuracy of Ductile Failure Assessments

Hodulak, L
Senior Scientist and head of Material and Component Assessment, Institut für Werkstoffmechanik, Freiburg,

Blauel, JG
Senior Scientist and head of Material and Component Assessment, Institut für Werkstoffmechanik, Freiburg,

Pages: 18    Published: Jan 1988

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Abstract

Ductile failure assessments of cracked specimens and components performed on the basis of the J-integral and the limit load concepts are discussed with particular interest in their ability and accuracy to predict actual failure loads. Possible sources of uncertainty in the modeling of material behavior and geometry are treated separately, comparing appropriate calculations with each other and with experimental data.

Especially approximate methods for evaluating J^applied are checked against finite-element calculations and are found accurate in all cases where plane models are relevant. The influence of the stress-strain law on the results of failure predictions is examined in detail, and a procedure is proposed for an appropriate evaluation of the Ramberg-Osgood constants in the Electric Power Research Institute estimation scheme. In addition, the influence of a variation of the material J-R curve and of the crack growth model in failure assessments is demonstrated for several examples.