Category Archives: Maths

More Python rotation functions

Posted on 23/02/2018 by dougaj4

The code described in the previous post includes a Python function that rotates 3D coordinates by an angle defined with two vectors, using Rodrigue’s Rotation.  I have now added this function to the IP2_py spreadsheet, where it is used in the … Continue reading →

Posted in Coordinate Geometry, Drawing, Excel, Link to Python, Maths, Newton, NumPy and SciPy, UDFs, VBA, xlwings | Tagged , , , , , , , , | Leave a comment

Fitting 3D circles to scattered points

Posted on 11/02/2018 by dougaj4

Following a comment at update-to-glob_to_loc3-and-loc_to_glob3-functions, I have modified the Python code at the linked site, so it can be run from Excel, via xlwings.  The spreadsheet described below, and the associated Python code, can be download from: 3DCirc.zip The original … Continue reading →

Posted in Coordinate Geometry, Excel, Link to Python, Maths, Newton, NumPy and SciPy, UDFs, VBA, xlwings | Tagged , , , , , , , | 7 Comments

Evaluating text with units and finding the neutral axis

Posted on 07/01/2018 by dougaj4

A few weeks ago a comment asked for guidance on finding the moment capacity of a reinforced concrete section.  This post will look at finding the depth of the neutral axis (NA) in a rectangular section, with a single layer of … Continue reading →

Posted in Beam Bending, Concrete, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , , , , , | 7 Comments

Section Properties with MeshPY, including torsion and warping

Posted on 09/12/2017 by dougaj4

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 , , , , , , , , | 11 Comments

Brent’s Method; Update and Examples

Posted on 06/12/2017 by dougaj4

Brent’s Method is a refinement of Newton’s Method for the numerical solution of any equation with one variable.  The User Defined Function (UDF) QuadBrent was described in:  The Inverse Quadratic Method 3 – Brent’s Method Following a recent question, I have … Continue reading →

Posted in Arrays, Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , | 5 Comments