Edinburgh Napier University

  This paper is concerned with the modelling of geometric imperfections in the finite element analysis of a built-up cold-formed beam assembled with mechanical fasteners. The objective of the study was to investigate the effects of contact interactions on the definition of initial geometric imperfections. With this aim, different shapes of geometrical imperfections were introduced in the numerical model of the beam. The imperfections were determined with eigenbuckling analysis and inelastic buckling analysis of the perfect model. An imperfection mode shape introduced by direct specification was considered as well. The influence of the different imperfection shapes on the non-linear response of the model was analysed and the reliability of the different modelling approaches was investigated on the basis of the experimental results obtained from four-point bending tests.