Investigation On Creep Interaction Of Double Embedded Cracks At Elevated Temperature

In the thermal power,petrochemical and other industries,the cracks were usually not exist alone,in pairs or combinations exist in many components which served at high temperature conditions.The interaction and combination of multiple embedded cracks would exacerbated cracks growth and greatly shortened the life of components.In this paper,double embedded cracks subjected to tensile loading and moment loading during creep regime were investigated and the features of cracks and material properties?e.g.crack aspect ratios a/c,relative crack depth a/t,relative distance s/c and creep exponent n?were considered and the applicability of the existing combination criterion under the high temperature creep mechanism was evaluated.The results showed that due to the crack interaction,the interaction factor distribution was observed to be asymmetric along the crack front.The multiple cracks interaction effect under the creep mechanism was always greater than that under the linear-elastic mechanism.What's more,the creep interaction factor greatly enhanced with the increasing depth of cracks and creep exponent and always gradually decreased as the position away from the each other but crack shape changed from elliptical shape to circular shape had 10%impact.In addition,the creep interaction factor determined by the average C*values along the crack front could better represent the multiple cracks interaction under tensile loading and moment loading.An empirical formulag ??? to determine the multiple interaction level considering the crack configurations and material properties was proposed for embedded cracks serviced at elevated temperatures.And the size of the equivalent single crack replacing the interacted multiple cracks should be determined by the creep interaction factor2c=?_Creep^a*max?2c ₁,2c ₂?.