J-integral and CMOD for external inclined cracks on autofrettaged cylinders

Abstract

Autofrettage is a well-known method to increase the load carrying capacity of the pressure vessels. The autofrettage outcomes can be contrary when the imperfections or material discontinuities are on the outer surface. In this study, the influences of the external inclined cracks on the fracture parameters in autofrettaged cylinders were studied. The inclination angles of cracks are different but they have the same depth. Crack mouth opening displacements and J-Integral values along the cracks front were investigated. The effects of autofrettage ratio, inclination angle, crack depth and length, the ratio of inner to outer radius and applied pressure were studied. The J-Integral values were calculated by using a modified equation taken from the recent literature, which includes the residual stress effects.

Applicability of the Modified Ritchie-Knott-Rice Failure Criterion to Examine the Feasibility of Miniaturized Charpy Type SE(B) Specimens

“…Usually, has a linear relationship with in this load range; thus, 22 is expected to be constant and independent of . Considering the fact that fracture was always observed to occur after 22 reached 22 for A533B steel [20] and for S55C steel in this work and in [14], the minimum that can satisfy 22 = 22 seems to correspond to the minimum observed with the specimen configuration and the material at a specific temperature. This finding is consistent with the opinion of Chen et al that "the minimum fracture toughness is a definite parameter determined by the specimen geometry and yielding properties" [26] and will be examined in more detail in the future.…”

“…The difference in , especially the bounding nature for large TST, clearly correlated with the difference in 33 at the fracture load. The idea to explain the TST effect by using the difference in 33 was supported by many researchers, such as [19][20][21][22][23][24][25].…”