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,







 

to be honest.
I have been plannig different type of wheelchair,too.

>>>>
Before that,
I would introduce a very popular comercial CFRP wheelchair.
 


This is the lightest wheelchair in the world.
made in Sweden.
weight is only 2.1Kg(4.63lbs).super light!. and  4.2kg(with rear wheels)
price is about 10000 dollars.

it looks that it is made of pre-preg CF and autocrave technique is used.
 Full monocoque frame.
it has 3 sections, right side frame, left side frame and crosmember.
each frame is baked in autocrave then connected.
back rest can be folded.




I tried this CFRP wheelchair.But I was NOT satisfied with its function.

because...
1st, the wheelchair is not stiff enough.I could easily bend the frame when I tilt my body.
     I guess only light weight may be  first priority.
2nd, its frame size variation is limited.it was too big for me. riding position was too high.
3rd, (like most wheelchairs) seat is something like Hammock.it is unstable.
     and my legs must be painful when I use this wheelchair for a long time
4th, legs are sometimes obstructive when I take the wheelchair into my car.
 

    

ultimately, I believe that this type of wheelchair has a serious problem.
that is...its center of gravity is too high.
unlike motorcycle,wheelchair is not more heavy than human body.
so total(wheelchair and human) center of gravity is very high especially super light wheelchair.
to addition, its center of pitching and rolling is too low.
(precisely,the wheelchair has NO suspension system.that makes the wheelchair more unstable.)

as a result, it is easy to pitch or roll over.
to solve this problem is one of my dreams.





Here is my second idea(plan2).
This has suspension system like a MTB.



in this case(image),
the suspension system lifts up wheelchair`s center of pitching.
if  center of pitching is close to the center of gravity,
the vehicle is more stable.

If the suspension system is add to the wheelchair,
a load is sustained by the suspension and shock is absorbed by the suspension, too.
That makes  easier to develop the frame because the direction of load can be controlled.



Anyway,
I need to design a new frame shape again and I will post it.

I would be happy if any comment or advice.