Hello!

I have a question about  sandwich core technique.
That is...

For example,
If I use  two set of  5mm nomex honeycomb core(10mm thick in total) to  make a sandwich panel,
is it  as strong as  a single 10 mm nomex honecomb core panel?
the  double 5mm sandwich has reasonable strength?
or the double 5mm sandwich is easy to break?


actually,
I want to build a curved sandwich panel.
I tried a 10mm thick  nomex honeycomb core at first,
but the 10mm thick core was too strong to bend.

 I wonder that if I use  a 5mm core,then laminate,bend  and add one more 5mm honeycomb core.
I mean,,  the sandwich is   CFRP>honeycomb core(5mm)>CFRP>honeycomb core(5mm)>CFRP.
If this idea is O.K. I will be able to build thick and strong curved sandwich panels.


Any advice,
I would be happy.

Thanks,







 

That should work.  It is essential to tie the two cores together as you have done with a thin layer of composite.  Otherwise the panel would just easily sheer along the join line.

Use a good structural adhesive/high strength resin on the join.  If done properly then the bond will be stronger than the honeycomb which is a good situation to be in.

The panel wont be much stiffer as a result of 2 cores. The physical extra material will add fractionally to the stiffness, but being in the dead centre, the loadings on it are more even.  

In terms of failure, logic would dictate a bent panel would sheer the core on the side under tensile force while the side under compressive force may have the core crush. That is assuming the outer skins don't fail first.  Without testing it would be hard to see the exact failure path.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

>> Warren san,

Your advice is very helpful and informative!  many thanks!


well...It seems that
Ｉ should be careful about a direction of loading.
loading on a bended CFRP>sandwich panel may cause  inside separation...
hum...
using bended sandwich panel is not that good idea, I feel.
If possible, I should look for a different choice.