Would a stacked honeycomb sandwich panel work?

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Would a stacked honeycomb sandwich panel work?

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BigChief	BigChief posted 9 Years Ago HOT Topic Details
Group: Forum Members Posts: 2, Visits: 50	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.
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Fasta	Fasta posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 3.5K	Generally this is not any stronger. Usually you can consider the middle of the sandwich as a neutral area where fibre layers would not be taking any loads. The outer skins take all the loads of compression and tension while the core mostly just holds the skins apart. In fact since your second proposal has just two layers on the outer skins then it would not be as strong as the first proposal that has three layers. Fastacraft Facebook page
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BigChief	BigChief posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 2, Visits: 50	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?
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Fasta	Fasta posted 9 Years Ago HOT Post Details
Group: Forum Members Posts: 468, Visits: 3.5K	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. Fastacraft Facebook page Edited 9 Years Ago by Fasta
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