GBTUL (acronym for "GBT at the University of Lisbon" and pronounced "G-B-Tool") is a program that performs elastic buckling (bifurcation) and vibration analyses of prismatic thin-walled members. The program enables viewing the GBT cross-section deformation modes and their participation in the solution of the problem being solved, allowing for an in-depth insight into the underlying mechanics. The user-friendly and intuitive GUI provides high-quality 2D and 3D outputs.

This program was developed with the financial support of “Fundação para a Ciência e Tecnologia” (FCT-MCTES Portugal), through the research project PTDC/ECM/108146/2008 “Generalised Beam Theory (GBT) - Development, Application and Dissemination".

When using GBTUL please cite:

Bebiano R., Camotim D., Gonçalves R., "GBTUL 2.0 − A second-generation code for the GBT-based buckling and vibration analysis of thin-walled members", Thin-Walled Structures, 124, pp. 235 - 257, 2018.

Download and unzip the GBTUL installer.

A brief tutorial is available here. 

Known issues:

The transverse extension modes should not be included when running the Analytical Solution.

In the "member analysis" separator, 3D plot window, the representation of the loads has some bugs. For instance, the end moments M1 and M2 are always represented along Y and Z, irrespective of the true principal axes directions (which are considered by the program).