A study on the representation of local effects in low order models for thin-walled rod members

Resumo

This work aims to explore alternatives to represent local effects, such as local buckling and plasticity, in low order models for thin-walled rod members. The discussion is carried out on a theoretical-numerical level, and illustrative examples are provided. The techniques that are explored stem from two different approaches: (i) direct enrichment of the rod kinematics and (ii) multiscale methods. Direct enrichment of low order kinematics usually leads to models with optimal computational cost, while still at the downside of having lower-order (still limited) kinematics. Models derived from the Generalized Beam Theory (GBT) are an example of such an approach. Multiscale methods, in turn, rely on results of higher-order theories (e.g., shells and 3D solids) to improve the performance of the lower-order model. The associated computational cost and accuracy vary widely with the imposed coupling level between the different scales. It is possible to have models ranging from full coupling at run-time the so-called strong coupling multiscale method to no coupling at all the higher-order models are used only to compute meaningful mechanical quantities that are passed on to the low order model at some point. The work is an on-going development of a PhD research by the first author, and the results provided so far are only partial.