Modelling Initial Geometric Imperfections of Steel Plane Frames Using Entropy and Eigenmodes

The article introduces an innovative approach to modelling initial geometric imperfections in steel plane frames. Initial imperfections are introduced using the analysis of normalised deformations of elastic buckling modes. The scale of these modes is assessed by applying Shannon entropy and potential energy analysis. The presented case study demonstrates a decreasing scale of the elastic buckling modes. The entropy computed from the deformation reveals a new perspective on buckling modes and provides a more profound understanding of steel frame behaviour. The case study results indicate that anti-symmetric buckling modes exhibit higher entropy than symmetric buckling modes. This entropy-based analysis enables the differentiation between symmetric and anti-symmetric buckling modes, which is particularly valuable when the critical buckling loads of sway and non-sway buckling modes are closely aligned or overlap.