Allowable basis for sandwich panels
Allowable basis for sandwich panels
(OP)
Dear engineers,
I trying to define guidelines for a stress engineer in aeronautic. We are making composite monuments for aircrafts/rotorcrafts. They are made with honeycomb panels (from Euro-Composite EC-PA-235G).
For the margin of safety calculation, what would you recommend to use: A-basis allowable strength values or B-basis?
By the way, does anyone have a clear datasheet of that panel?
Thanks for your coming answers!
Ben
I trying to define guidelines for a stress engineer in aeronautic. We are making composite monuments for aircrafts/rotorcrafts. They are made with honeycomb panels (from Euro-Composite EC-PA-235G).
For the margin of safety calculation, what would you recommend to use: A-basis allowable strength values or B-basis?
By the way, does anyone have a clear datasheet of that panel?
Thanks for your coming answers!
Ben





RE: Allowable basis for sandwich panels
Have you contacted the manufacturer of the panels to see if they have any data? It is not likely that you will find publicly published allowables. You should plan a test program to obtain them.
RE: Allowable basis for sandwich panels
I do not have an agreement with the agency yet. I was more looking for a reference I could use for that (like MIL-HDBK-17).
But thanks for your answer.
RE: Allowable basis for sandwich panels
I think there is an AC for interior structures; don't have time to look for it now. Otherwise, there is not much clearly written down about what is single and multiple load path structure; though most of a commercial airplane is considered multiple load path and is sized with B-basis values.
RE: Allowable basis for sandwich panels
GAMA Publication 13 may be of some help, though it doesn't appear to make an explicit statement on this issue.
In my opinion, SW is right in that most interior monuments are multiple load path - and as such B-Basis allowables should be acceptable.
However, in my experience, the certifying authorities require, or are much more comfortable with, the usage of A Basis allowables. In cases where I've needed to use B Basis, I've needed a seperate anlaysis or justification to demonstrate the multiple load paths. It is often easier to design to the A Basis values.