Beam actions and deflections, 3D or 2D

Two new functions have been added to the ConBeamU spreadsheet, last discussed here.

The new version can be downloaded from, including full open-source code.

The new functions, BeamAct3D and BeamAct2D calculate forces, moments, deflections and rotations along a 3D or 2D beam under specified end conditions and loading.  The output is calculated based on the conditions specified at End1, and optionally the error in the calculated values at End 2, compared with the input values, may be returned.  If this option is not used the End2 data is ignored.

The examples below show input for a uniform beam, but the beam may be subdivided into any number of segments with differing section properties.  The current version of the functions performs linear analysis only, but the section properties can be easily adjusted on the spreadsheet, based on the output actions, to provide non-linear materials analysis.  Later versions will have this functionality built-in, and will also provide for geometric non-linear effects.

Details of the function input and output are shown in the screenshots below (taken from the Functions sheet of the spreadsheet).  For more details of how to use Excel User Defined Functions and Array Functions see: Using Array Functions and UDFs.


BeamAct Functions Input 1


BeamAct Functions Input 2

The output consists of 12 or 6 columns for the 3D or 2D version respectively:


Examples of both functions are found on the BeamAct sheet:


BeamAct3D Input


BeamAct3D Input


BeamAct3D Output; click for full size view


BeamAct3D Deflection Results Compared with Strand7


BeamAct2D Input 1


BeamAct2D Input 2


BeamAct2D results


BeamAct2D Results compared with Strand7

This entry was posted in Beam Bending, Excel, Finite Element Analysis, Frame Analysis, Newton, Strand7, UDFs, VBA and tagged , , , , , , . Bookmark the permalink.

2 Responses to Beam actions and deflections, 3D or 2D

  1. Achille says:

    at first glance I do not see the use (or benefit) for this new application.
    Can you please show us what are you forseeing?


    • dougaj4 says:

      Primarily if you have results from a frame analysis, which just gives you actions and deflections at each end of the member, these functions allow you to calculate the forces, moments, rotations and deflections along the length of the member.


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