One of the disadvantages of the blog format is that valuable resources tend to get lost somewhere in the archives. To help make them a bit more visible, for the next month or so I plan to post links to the spreadsheets available for download here (127 in all), together with a short description and a link to the most recent blog post for more details.
To start, here are two spreadsheets performing buckling analysis:
Buckling of columns with varying cross section
Download from: http://interactiveds.com.au/software/Frame4Buckle.zip
This spreadsheet is based on the Frame4 spreadsheet, modified to carry out a buckling analysis of any straight member subject to axial load, including stepped or tapered cross sections. The buckling load is found using the method of Vianello, described in a paper from the University of Ljubljana. This is an iterative method using successive approximations of the deflected shape.
Typical input and results are shown in the screen shot below:
The buckling shape may be plotted to a chosen scaled deflection:
Download from: http://interactiveds.com.au/software/Frame4buckle-ring.zip
The buckling spreadsheet described above has been modified to allow the input of a quarter circular arch (which with appropriate end conditions is equivalent to symmetrical effects in a full ring), or for a smaller portion of an arc. The spreadsheet also allows different options for the change in direction of the applied load after deformation of the ring, and the ring may be either specified with a constant cross section or a series of stepped sections.