Experimental and analytical fracture assessment of 165-mm diameter AISI 304 seamless piping containing a circumferential through-wall crack

Abstract Field engineers often face the need to assess the residual strength and remnant life of cracked components within a limited time. A number of engineering methods for the assessment of elastic-plastic fracture behaviour of cracked components proposed in the past decade may be used for this purpose. These include the net section plastic collapse method, the J- integral estimation method and the R6 (Revision 3) failure assessment method. The primary aim of these methods is to obtain fracture behaviour prediction with a reasonable degree of accuracy without resorting to a complicated full-length numerical elastic-plastic fracture mechanics analysis. Systematic comparison of these different methods for assessing the relative degrees of accuracy and conservatism based on experimental results are still very limited. In the current work, some fracture experiments on 165-mm diameter piping with through-wall cracks were conducted. Based on these data, the predictive capabilities of the three engineering assessment methods are compared. The relative merits and limitations of each method are discussed in the light of these evaluations. The results suggest that the J- integral method has the best overall accuracy but requires the most detailed baseline material properties data. The R6 Revision 3 method offers a number of choices which vary in complexity and amount of data needed; this method tends to give relatively more conservative results than the J- estimation method. The net section method is the simplest among the three and gives reasonable predictions of maximum load in the current case.

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