topic Re: Composite Structures - error in total thickness in Modeling

Composite Structures - error in total thickness

CarlM — Fri, 19 May 2023 20:36:33 GMT

Hi,
I have an issue with the summation of the total thickness of a composite structure - the addition is simply wrong!
in the attached image: 13+12+120+12+13 = 170, not 169...
Is this a known error?

Re: Composite Structures - error in total thickness

vistasp — Wed, 28 Nov 2018 06:27:10 GMT

Had you, by any chance, typed in 12.5 for the first and last skins? Even if they shows up as a full integer (13) in the dialog box, they would be getting calculated as 12.5.

It could be any other pair of skins too...

Re: Composite Structures - error in total thickness

Barry Kelly — Wed, 28 Nov 2018 07:08:24 GMT

CarlM wrote:
Is this a known error?

Yes - user error.

Check and type the thicknesses again.
If you have 11.7 it will round up to 12 if you have the decimal precision turned off.
So you may well have some slightly smaller thicknesses there that you aren't noticing.
See my images.
One is correct but the other I typed 11.7 and 12.7 - they still show as 12 & 13 but total with the correct figure of 169 (actually it would be 168.8 but will round up to 169).

Barry.

Re: Composite Structures - error in total thickness

CarlM — Wed, 28 Nov 2018 07:53:36 GMT

vistasp and Barry,

You were both right!!
Thanks a lot for such quick replies!

I retyped the thickness for each and one and the math adds up again - tricky little round up that has caused me quite some headache.

Thanks again!