# FEM, FEA, Frame, Moment, Shear, find Stiffness Matrixx

1. Feb 24, 2015

### McLovinn

1. The problem statement, all variables and given/known data
Hi,

I need some help analysing this frame. First of all i bellive its hard, if not impossible, to get as detailed results by hand calculations as my softwear CSI Sap2000. Becourse of shear and axial deformation.

Is it possible to obtain the stiffness matrix of this frame at all, or do i need to look at different methods.

Can you pleas tell me where to ask if this is wrong forum?

Thanks, most sincerly!

2. Relevant equations
http://www.sut.ac.th/engineering/civil/courseonline/430332/pdf/07_matrix_frame.pdf

3. The attempt at a solution

Not even sure if its possible.

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• ###### Frame, matrix.jpg
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2. Feb 24, 2015

### SteamKing

Staff Emeritus
You shouldn't have a problem creating the stiffness matrix for your frame by hand, if that's really what you want to do. Even for such a small frame, it's going to be pretty tedious.

I think one problem you might have with creating the stiffness matrix is what to do about the joints which connect the red parts of the frame to the blue parts. These four joints appear to be pinned connections. As such, each joint will only support forces; no moments can be transmitted, therefore, you must modify your stiffness matrix to reflect this situation.

Good Luck!

Of course, creating the stiffness matrix is only one step in analyzing this frame.