Metamorphs Journal: Plane Frame Analysis

Sample03

I have taken the plane plane frame analysis application I previously blogged about here, and ripped out all the DOS based full screen graphics and reduced it to a command line application, and made available for download. To me this is not diminished capability but an enhancement. I never used the user interface as I auto-generated the data files using Borland Quattro Pro (QPro) spreadsheet. However whilst I could launch pframe from within QPro I had to open the data file, run the analysis and then save the results: three steps where one would have done. Now with a command line parameter, the data file can be created and then cpframe can be called from an MS Excel routine to run the analysis on the data file and produce the results file. Though it can be simply used at the command prompt. If type name in without a file name then it will show a brief message on how to use.

cpframe usage

run cpframe

Other wise it is simply called with a data file containing the definition of the structural model, a single load case per file, for example:
cpframe refF_wrk.dat

screen dump as program runs

Which will then display its progress and generate a results file with the file extension .rpt for report. The report can be read with a simple text editor like notepad, and similarly data files can be created with notepad. Though the primary intent is that data files will be auto-generated by some other application.

Sample01

There are no graphics with this version. Since the graphics in the original version have full control of the graphics screen, its not fully compatible with use in Windows. It works in the Windows XP command prompt but does not seem to work in Windows 7. However can always load FreeDOS onto a bootable flashdrive and run from there.

Noting the benefit of being able to see the geometry and the direction of loading to check the validity of the model, in the near future I will release a version with the menus and graphics put back. However I will be removing the menus for data file creation, as objective is that data files will be created by an external application and I don't wish to expend time fixing such menus up. The source code has already been transferred to Delphi and a windows version part written. We also have a version in Excel/vba (.xla) which is providing the structures engine for cold-formed steel carport and veranda software. {Sorry! Cannot release the original version as the report file it produces implies we did the design of the structure being analysed. Plus it was compiled back in 1996 using Turbo Pascal, and finding the complete source code to compile something similar got complicated.}

Any case the idea isn't to write a stand alone frame analysis application but provide a library, or COM automation server or .net component which can be referenced in other applications, which need structural analysis as a component of a much larger system. A command line application provides a stepping stone towards such objective, it allows use in other applications, but in a more limited way than is possible if can send data direct into the analysis.

In future posts I will provide more sample data files, and an MS Excel workbook with vba code to write such data files. Resources for calculating wind loads and checking capacity of members can be found over on my ExelCalcs profile. Of course meshing it all together to fully automate simple buildings at the point of sale is a fairly massive exercise.

For small manufacturers approaching small engineering consultancies the one thing the consulting engineers have missing from their tool box is frame analysis. The consultants typically use MicroStran, Spacegass or Multiframe to conduct analysis, and therefore the engineers do not have their own tools to integrate into the software they are asked to develop. The simple solution to this is to use Kleinlogel formula, however new publications with such formula are now rare, and the older publications difficult to get hold of. Further there is the problem of finding the appropriate formula for the structure being considered. Sure they could attempt to derive the appropriate formula but that is more time and effort, and as the manufacturer introduces more variety into the structures more formulae are required. Where as matrix structural analysis is more general purpose, once again there is still the problem of writing the source code and testing it. Also transforming theory into source code not so easy, and books with sample source not so readily available. Though a search of the web indicates recent engineering students/graduates may have experimented with matrix structural analysis using either MatLAB or SciLAB.

My previous contribution to easing this shortfall of analysis tools has been:

Release height/span charts showing the limitations of c-sections for the typical gable frame shed so that can limit the number of standard designs produce detailed calculations for.
Release MS Excel workbooks with Kleinlogel calculations in the worksheet.
Release MS Excel workbook with Kleinlogel formula as vba code for gable frame.
Release table of Contents of Kleinlogel formula book
Release a simple program for checking gable frame size based on Kleinlogel formula.

All of these tools we use in-house for quick decision making, though admittedly my gable frame spreadsheet contains the full design for cold-formed steel: still I believe I've provided all the resources for interested parties to build something similar better adapted to their needs. All the previous releases however have been focused on the gable frame (sample01) where as design of the so called American barn style structure (sample03) is often wanted by manufacturers. Using plane frame application this is now more practical to accomplish than setting up worksheet calculations in Excel.

The program can be downloaded here.

DISCLAIMER :
Users of the software must accept this disclaimer of warranty :
The software is supplied as is. The author disclaims all warranties, expressed or implied, including without limitation, the warranties of merchantability and of fitness for any purpose. The author assumes no liability for damages, direct or consequential, which may result from the use of the software.

Revisions:
[25/01/2014] Original

[23/04/2016] Changed download links to MiScion Pty Ltd Web Store

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Saturday, January 25, 2014

Plane Frame Analysis