DNV GL-ST-F101 Combined Loading Criterion: Background and Derivation

The local buckling criterion for combined loading in DNV GL-ST-F101 (DNV-OS-F101) [1] was introduced in its present format in the 2007 revision. The formulation is based on a plasticity theory, modified for strain hardening and, finally, finite element calculations. Derivation of this formula has not been published before and is given in the paper. Further, there is some confusion in the industry with respect to the use of effective force in the formulation which will be explained. This paper is supported by a paper that compares this formulation with tests and other criteria, Fyrileiv et al [2].