Category Archives: Frame Analysis

3D Frame with zero stiffness hinges

The previous version of 3DFrame allowed for spring releases at beam ends, but if the release stiffness was entered as zero it was treated as a rigid connection for that freedom.  Effectively zero stiffness releases could be modelled by entering … Continue reading

Posted in Beam Bending, Excel, Finite Element Analysis, Frame Analysis, Newton | Tagged , , , , , | 3 Comments

Transferring large arrays with Pyxll

Pyxll is a commercial Excel add-in linking Excel and Python.  The latest version  offers greatly improved performance in transferring data between Excel and Python as Numpy arrays, amongst many other new features and improvements. To check what this means in practice, … Continue reading

Posted in Arrays, Excel, Frame Analysis, Link to Python, PyXLL, UDFs, VBA | Tagged , , , , , , | Leave a comment

Using Redim and 3DFrame

I recently received a query about the 3DFrame spreadsheet failing to run.  The problem was that the code was trying to Redim an array that had not been previously created with a Dim statement.  This does not cause a problem … Continue reading

Posted in Excel, Frame Analysis, VBA | Tagged , , , | 1 Comment

Beam geometric non-linear effects

A quick and convenient way to allow for the effect of deformations on the behaviour of beams and columns under axial load is to adjust the beam stiffness matrix, so that the calculated deflections are in equilibrium with the applied … Continue reading

Posted in Beam Bending, Excel, Finite Element Analysis, Frame Analysis, Newton, UDFs, VBA | Tagged , , , , , , | 2 Comments

Frame Analysis Resources

I recently discovered: Matrix Structural Analysis, 2nd Edition, by McGuire, Gallagher, and Ziemian. which is available for free download: Description The aims of the first edition of Matrix Structural Analysis were to place proper emphasis on the methods of matrix … Continue reading

Posted in Finite Element Analysis, Frame Analysis, Newton | Tagged , , | 1 Comment

Section Properties with MeshPY, including torsion and warping

I recently discovered robbie van leeuwen’s structural engineering blog, which has an open-source set of Python routines for calculation of section properties, including torsion and warping constants.  The program uses the MeshPY Library for generating the finite element meshes required … Continue reading

Posted in Beam Bending, Concrete, Excel, Finite Element Analysis, Frame Analysis, Link to Python, Maths, Newton, Numerical integration, NumPy and SciPy, Strand7, UDFs, VBA, xlwings | Tagged , , , , , , , , | 7 Comments

Stepping through 3DFrame

Following a recent comment this post looks at the code for setting up the stiffness matrix for a 3D frame, and how to step through any selected part of the code. The general procedure for setting up a 3D stiffness matrix, … Continue reading

Posted in Beam Bending, Excel, Finite Element Analysis, Frame Analysis, Newton, UDFs, VBA | Tagged , , , , , | Leave a comment