Reference stress J estimation for cylinders with axial surface cracks under combined pressure and global bending moment

Abstract

Several available limit load solutions for cylinders containing axial surface cracks, including the R6 global limit pressure solutions and newly published global/local solutions for combined pressure and global bending moment, are validated for J predictions via the reference stress J scheme using 336 finite element (FE) elastic-plastic J cases. The results for pure pressure loading show that the R6 global Tresca limit pressure solution for internal cracks is reasonably conservative but that for external cracks needs to apply a factor of 0.95. The results for combined loading show that the R6 global limit pressure solutions are non-conservative when the bending moment is significant and the newly published global/local limit load solutions can lead to good J predictions but the predictions may be non-conservative for some cases. Modifications to the newly published global/local limit load solutions are proposed and further validation using the FE J results shows that both the modified new global/local limit load solutions can lead to reasonable conservative J predictions when used with the reference stress J scheme.