Nominal bending strain for pipe

Orcaflex:

(half the pipe diameter) / (radius of curvature)

Abaqus thin pipe:

(pipeline MR) / Radius_of_curvature

pipeline MR = (half the pipe diameter - t/2)

Abaqus thick pipe:

inner fibre/mean/outer fibre has 3 level of strains:

(half the pipe diameter - t) / Radius_of_curvature

(pipeline MR) / Radius_of_curvature

(half the pipe diameter) / Radius_of_curvature

A sample case of rotate and then release looks like this: