Category Archives: UDFs

Asymmetric Catenary Function

Posted on January 31, 2020 by

Back in 2009, I posted a user defined function (UDF) to generate a catenary curve, that could be used together with the Excel Solver to generate a curve of a specified span and sag: A catenary function Following a discussion … Continue reading →

Posted in Coordinate Geometry, Curve fitting, Excel, Maths, Newton, UDFs, xlwings | Tagged , , , , | Leave a comment

Column buckling under multiple loads

Posted on January 20, 2020 by

Following another buckling discussion at Eng-tips I have modified my Frame4-buckle spreadsheet to allow input of multiple axial loads at any point along the column, along with any number of sections with different section properties.  Background on the method used … Continue reading →

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

Python Traps

Posted on January 1, 2020 by

When converting existing VBA code to Python there are a number of obvious changes to the syntax that need to be made for the code to run at all, but there are also a number of not so obvious traps … Continue reading →

Posted in Arrays, Excel, Link to Python, Newton, NumPy and SciPy, PyXLL, UDFs, VBA | Tagged , , , , , , , , | Leave a comment

Excel Dynamic Arrays

Posted on December 8, 2019 by

Previews of dynamic arrays in Excel have been available for some time through the “Insider” programme.  They are now being published to general subscribers through Office 365 monthly updates: Further information is given at: Easier array formulas and Dynamic array … Continue reading →

Posted in Arrays, Excel, UDFs | Tagged , , , , , | Leave a comment

A problem with integers in VBA

Posted on October 1, 2019 by

A recent question at Quora asked: “Why am I getting an overflow error in Excel VBA when doing a simple arithmetic calculation like str1 = 24*60*30 where str1 is a variant or long or double?” I hadn’t encountered that problem … Continue reading →

Posted in Excel, UDFs, VBA | Tagged , , , | Leave a comment

Solving the Lagrangian Point equation for the Moon

Posted on June 23, 2019 by

This post was prompted by a recent question at Fitting high order polynomials, asking for Excel methods to solve the equations for the radius of the Moon’s Lagrangian Point 1. All the methods described in this post have been added to … Continue reading →

Posted in Excel, Maths, Newton, UDFs, VBA | Tagged , , , , , , | 3 Comments

ULS design of circular reinforced concrete columns

Posted on June 9, 2019 by

The RC Design Functions spreadsheet has been updated (to Version 8.04) with the addition of a CircU function for ULS design of circular reinforced concrete sections under combined bending and axial load.  The new version, including full open-source code, may … Continue reading →

Posted in Beam Bending, Concrete, Excel, Newton, UDFs, VBA | Tagged , , , , , , , , , , , , , | Leave a comment