Talk Composites - The Forum for Advanced Composites

Would a stacked honeycomb sandwich panel work?

http://www.talkcomposites.com/Topic22347.aspx

By BigChief - 11/29/2016 10:46:10 PM

Let's say I was going to make a sandwich panel:

---3 layers of carbon fiber---
---1-inch nomex honeycomb---
---3 layers of carbon fiber---

What if I instead made:

---2 layers of carbon fiber---
---half-inch nomex honeycomb---
---2 layers of carbon fiber---
---half-inch nomex honeycomb---
---2 layers of carbon fiber---

Both sandwich panels total the same amount of material and weight... would the second option be as stiff/strong?

Are there any best practices on how many layers of carbon fiber to honeycomb would give the best strength-to-weight ratio? It would be nice to have a general idea without resorting to FEA tools.
By Fasta - 11/30/2016 7:44:45 AM

BigChief (30/11/2016)
Thank you for the help. If I kept the 3 layers on both the top and bottom and put a single 7th layer of prepreg carbon fiber in the middle between the two sandwich panels (to give them both a surface to adhere to), then it shouldn't be significantly weaker than the first proposal, correct?


That's right although some might consider that joining honeycomb like this could be a structural risk.

I know I said the core is neutral but it still transfers loads from one side to the other. You really need to satisfy yourself that it is ok with a small test or other?? It likely is ok but you can see that a join like this is somehow a disruption to the honeycomb as the cells will not likely match up like a full 1" thick would be. Foam cores can be bonded without concern.