Prediction of sheeting failure by an ultimate failure model using the fictitious strain method

First-generation sheeting may fail if loaded by combined bending moment and concentrated load. This failure can be predicted by an existing ultimate failure model that calculates the out-of-plane deflection of a part of the compressed flange due to the concentrated load. This deflection is then used as an imperfection for Marguerreʹs plate equations. The sheeting is assumed to fail if the plate in Marguerreʹs equations starts to yield. In this paper, a major improvement of the ultimate failure model is presented by replacing the complex Marguerreʹs equations with the fictitious strain method. This method predicts plate failure by an analytical model describing pre- and post-buckling behaviour and an empirical expression for the fictitious elastic strain at failure determined by finite element simulations. The new prediction method is compared with Eurocode3. It is shown that the ultimate failure model using the fictitious strain method performs equally well as Eurocode3, but provides more insight in the failure behaviour. Finally, suggestions to improve the method further are given based on a parameter study.