## Frame Analysis with Excel – 5; Large frames in Excel 2003

Continuing from: Frame Analysis with Excel – 4, 2D frame analysis

The solution presented in the previous post in this series made use of the Excel built in functions MINVERSE() and MMULT(), which restricted the size of problem that could be handled, especially in versions earlier than 2007.  These functions have now been replaced with a VBA Gaussian Elimination routine, and the matrices are no longer written back to the spreadsheet, so frames with more than 250 degrees of freedom can now be tackled.  There is still plenty of scope for improving the efficiency of the solution routine, but nonetheless the present system is adequate for quite large frames, so for the next few posts I will concentrate on improving the functionality:

• Provision for moment and translational release of member ends
• Output of member actions at nodes or intermediate points
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### 5 Responses to Frame Analysis with Excel – 5; Large frames in Excel 2003

1. napster says:

Hi Sir,

Thanks to your blogs, though i am a newbie, I have learned a lot about FEM. I have this hobby of writing simple applications related to Civil engineering practice( written in VB), and i came up with the idea of making doing FEM Frame analysis in 3D. Though the stiffness matrix is not the hard to find, I was having trouble finding a way to determine the rotational matrix of a 3D element.
I was just wondering if you could help me with this?

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2. dougaj4 says:

Napster – have a look for “Programming The Finite Element Method” by Smith and Griffiths. They have full details of FE applications, including 3D frame analysis. I’m also planning to look at it here, but not for some time.

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• napster says:

ill try to look into it.. thanks… i have been looking through many references, however the rotational matrix for 3D frame were never emphasized… 😦

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