ASME VIII Div 2 (2023 Edition) Part 5 - Elastic-Plastic Buckling Method B

[Russ A]

Hi all,

I am struggling to understand the correct approach in ASME VIII Div 2 Part 5 2023 Edition for elastic-plastic buckling (Method B). Step 1 is clear. Step 2; is the suggestion that the linear elastic buckling displacements are factored by the manufacturing tolerance (or measured imperfection) so that the peak displacement in the Step 1 buckling analysis is that of the max tolerance/measured? Step 3 these displacements are then imposed on the elastic-plastic model before applying the loads? Reading it that's what it seems to imply, but for a few reasons that doesn't make sense to me. Happy to hear other people's thoughts on the approach.

Thanks and regards

 

[TGS4]

Russ - that's exactly it. The elastic-plastic analysis is perturbed by an initial imperfection, of a magnitude equal to the maximum of the tolerance, in the shape of the most likely elastic buckling mode. There is a tight correlation between the magnitude of these imperfections and the design margin.