Jacobsen Steel Tunnel Liner Buckling Equations

[artome]

Hello,

I hope this is the right place to post this thread.

I have a project in which I am to attempt to write a code in Excel's VBA language to run a program within Excel to calculate the values of alpha, beta and the critical buckling pressure. I have been mulling around with the concept but I just can't seem to figure out how to properly implement it.

So far, I've looked into E.T. Moore's work published in 1989 using what looked to be Fortran, where he creates a program to determine exactly what I've set out to do. I've also looked into different numerical methods to try to implement in Excel's limited VBA code, more specifically Newton's method.

Because of the complexity of the equations, the partial derivatives for each unknown are complicated to produce, and so I haven't been able to progress.

I was wondering if anyone else has had a similar undertaking, or has touched these equations. I am looking for some guidance; if someone has a suggestion (or the partial derivatives! ), I would be extremely grateful.

Thanks!

 

[bpiermat]

Hi! I have a mathcad file that will do the calculaton for you. I have not had time to update it to MathCAD prime though, so its an older (not free version). Will this work for you?

Ben

 

[IDS]

I have an Excel spreadsheet that does the Jacobsen calc. If you send an e-mail to dougaj4 at gmail I'll send you a copy.

I have also attached a paper I did a few years ago, comparing various buckling solutions with FEA results.

Also you might be interested in the blog post below, which has an Excel iterative solver using Brent's Method.

http://newtonexcelbach.wordpress.com/2010/04/13/the-inverse-quadratic-method-3-brents-method/

Doug Jenkins
Interactive Design Services

http://newtonexcelbach.wordpress.com/