Analysis of the loss of stability of open profile thin-walled rods, into account the imperfections of the form

It was made the analysis of influence geometric imperfections to form on stability centrally compressed thin - walled rods open profile with different wall thickness. The software complex finite element NASTRAN used create computer models rods. Shelves and walls are modeled as a set quadrangular shell elements six degrees freedom in node. Geometric first general loss an ideal surface, which obtained from linear calculation is rigidly fixed at bottom articulated top. With help specially created program, amplitude shape proportional Calculations open-profile were performed formulation by Lanzosch method, nonlinear Newton-Rafson method. Was received values critical load corresponding forms deformation surface taking into account amplitude. research results compared experimental, 2016 laboratory Faculty Civil Engineering, University Zagreb (Croatia), analytical numerical calculations using ABAQUS 2020 Brest State Technical (Belarus). Comparative showed that compressive forces this work computational procedures package NASTRAN, less than experimental. analytically bigger all researchers. coincidence detected case rod thickness 0.0011 m mismatch 0.003 m. research, simulated increase had little effect forces. This indicates model not most dangerous for such profile, mounting load. Therefore, there need further perform modeling imperfections, example, their ultimate state action operating load, formulation.