Re: stiffness coefficient program

From: <leop_at_lyradev.com>
Date: 18 Jun 2015 16:48:34 -0700

To answer Ray's question, the file in in the files section of this group. It is adjacent to the version 25 file uploaded by Brett.

 To answer Bill's concern, I would not have said anything if I had not run tests. As I said, the two versions of the program are different only for certain ranges of input. The density stays the same for both versions but the stiffness coefficient sometimes differs with version 25 giving a higher, incorrect answer.
 

 Use these parameters for example
 

 length: 18"
 width: 1.25"
 thickness: 0.062"
 buckling load: 80 grams
 

 Version 25 gives 5.0 lb/ft3 density and 138.19 SC
 

 Version 27 give 4.98 lb/ft3 density and 123.69 SC
 

 As one can see, the densities are the same but Sc's differ. This is actually fairly mild difference and other input parameters can give a 25% difference for SC.
 

 Version 25 does not have a bug. The internal parameters appear to have been changed for certain ranges on input. My understanding is that these changes were not made by Fred Rash, the primary author of the program and I think that this assumption is substantiated by the output from version 27.
 

 I do not use any version of this program as I have written my own program from the original papers on the stiffness coefficient. Version 27 and my program agree as far as I can tell.
 

 LeoP
Received on Thu Jun 18 2015 - 16:48:34 CEST