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Last week, I performed a structural analysis of a frame made from Supa100 sections. These steel sections are essentially SHS100x3 with slotted holes. I needed section properties for FEA analysis, and while I attempted to use BXS user-defined sections in Strand7, we can all agree that cross-section calculators in FEA packages leave much to be desired.
I searched for a free cross-section calculator capable of analysing sections from CAD files with warping and plastic properties. Finding none, I decided to create one myself. As a long-time fan of Robbie's Python package https://github.com/robbievanleeuwen/section-properties, I wanted to use Ibrahim Fahdah's .NET adaptation https://github.com/IbrahimFahdah/CrossSection.Net. However, upon testing the .Net adaptation, I found the Cholesky decomposition failing in certain cases with ill-conditioned matrices. To address this issue, I implemented an LU decomposition with pivoting for cases where the K matrix isn't positive definite. While significantly slower, it's more robust. My modified adaptation is here https://github.com/dmitryzelenkin/CrossSection.Net.
Today, I've added a user-friendly web interface for that section calculator https://spectacalc.com/listing/30/47. The tool is free and does the section analysis using the code in github repositories above. The tool functionality:
- Analyse cross-sections by simply drag-and-dropping DWG/DXF files
- Calculate warping and plastic properties
- Get results in your CAD file's native units (so, the tool is unitless)
Notes:
- The holes are detected similar to SVG fill rule "evenodd", meaning if the point is contained in even number of regions, it will be considered as a hole.
- I've tested the tool mainly on closed polylines with Bulge properties. So if the tool doesn't work with your CAD file, please send me the CAD file on email dmitry.zelenkin@spectacalc.com and I will do my best to fix the tool.
Looking for feedback:
- Would radius of gyration or principal axes properties be useful additions?
- Should we implement composite action analysis for closed sections?
I searched for a free cross-section calculator capable of analysing sections from CAD files with warping and plastic properties. Finding none, I decided to create one myself. As a long-time fan of Robbie's Python package https://github.com/robbievanleeuwen/section-properties, I wanted to use Ibrahim Fahdah's .NET adaptation https://github.com/IbrahimFahdah/CrossSection.Net. However, upon testing the .Net adaptation, I found the Cholesky decomposition failing in certain cases with ill-conditioned matrices. To address this issue, I implemented an LU decomposition with pivoting for cases where the K matrix isn't positive definite. While significantly slower, it's more robust. My modified adaptation is here https://github.com/dmitryzelenkin/CrossSection.Net.
Today, I've added a user-friendly web interface for that section calculator https://spectacalc.com/listing/30/47. The tool is free and does the section analysis using the code in github repositories above. The tool functionality:
- Analyse cross-sections by simply drag-and-dropping DWG/DXF files
- Calculate warping and plastic properties
- Get results in your CAD file's native units (so, the tool is unitless)
Notes:
- The holes are detected similar to SVG fill rule "evenodd", meaning if the point is contained in even number of regions, it will be considered as a hole.
- I've tested the tool mainly on closed polylines with Bulge properties. So if the tool doesn't work with your CAD file, please send me the CAD file on email dmitry.zelenkin@spectacalc.com and I will do my best to fix the tool.
Looking for feedback:
- Would radius of gyration or principal axes properties be useful additions?
- Should we implement composite action analysis for closed sections?
