Links to two popular and freely-available thin-walled structures analysis tools:
CUFSM – Constrained and Unconstrained Finite Strip Method
http://www.ce.jhu.edu/bschafer/cufsm/
From the developer Dr. Ben Schafer: “The elastic buckling analysis of thin-walled cross-sections has long benefitted from the use of finite strip analysis which has the unique ability to provide complete and relevant stability solutions in a compact and powerful form.
CUFSM provides a full suite of finite strip analysis and related tools for thin-walled sections including: signature curve analysis, general end boundary conditions, generalized loading, built-in cross-sections, and constrained finite strip solutions for modal decomposition and identification. Additional tools are also provide for plastic section analysis, section property analysis, ancillary analyses to approximate members with holes, tools for interacting with the beam finite element software MASTAN, and even classical beam-theory global only buckling analysis with an integrated version of CUTWP. CUFSM has a wealth of tools for learning about thin-walled member stability and we invite you to download and play with the software.”
GBTUL – Generalized Beam Theory
http://www.civil.ist.utl.pt/gbt/?page_id=6
From the developer: Rodrigo Goncalves, “GBTUL (acronym for “GBT at the University of Lisbon”) is a freeware program that performs elastic buckling (bifurcation) and vibration analyses of prismatic thin-walled members. It implements the latest formulations of Generalised Beam Theory (GBT), a thin-walled bar theory that (i) accounts for local deformation and (ii) provides an advantageous representation of the deformation field, as a combination of structurally meaningful cross-section deformation modes.
Taking advantage of the GBT modal features, the program provides information and visualisation of the member deformation modes. Moreover, it contains tools that make it possible to select the deformation modes to include in the analysis, thus allowing for a in-depth insight into the mechanics of the problem being solved. It is possible to analyse members (i) made of one or several isotropic or orthotropic materials, and (ii) exhibiting various common support conditions (e.g., simple supports, fixed supports or free ends). In the buckling analyses, the user is able to specify any combination of arbitrary axial force, bending moment and bimoment (longitudinal) diagrams.”