Investigation of Nonlinear Behavior of a Metal Rod Using FDM Macro

This article illustrates the process of creating macro and non-linear calculation of stress-strain state of metal rod, which allows to make preliminary calculations in Grasshopper environment, taking into account non-linear effects for steel structures. The proposed approach is especially interesting because it is based on the finite difference method (FDM), which does not require large computing power, is implemented in a common language that allows the use of open-source code without the use of expensive software and can be used for in-depth analysis of the operation of the rod. Meshing is realized also in Grasshopper and affects the results accuracy crucially. The example of an approach is given as the calculation of a cantilevered compressed-flexible rod with a round tube section, an I-section and a channel section, considering physical and geometric nonlinearities, with the modelling of a shape and the formation of data on the geometry by Grasshopper and the subsequent import of the obtained data into a code developed on Python3. The FDM results can be compared to more common FEM calculation, the example of such comparison is given and the discussion about the reasons of convergence or non-convergence. In prospect, similar technique can be used for some materials, which characteristics are not standard, and their features are not included in existing FEM-software model options, and also for objects of complex geometrical shapes.