Sandwich panel with different CORE heights

[airmail]

Hello colleagues:

I have a sandwich panel with different core heights because of several actuators that are located in its inner area (it is necessary a height change).

In a transverse cut you can see (from left to right): monolitic area, core of 25,monolitic area, core of 10, monolitic area, core of 25 and monolitic area again. Only the borders are simply supported, so intermediate monolitic areas cannot be considered as a support.

How can I analyse it? Thank you very much for your help

 

[SWComposites]

Are you trying to do a FE or hand analysis? What are the boundary conditions on the panel? How is it loaded? what do you mean by "core of 25"? Core thickness = 0.25 inch?

 

[GBor]

airmail:

I'm with SWComposites...we need some more details, but I would say that it sounds like you are talking about a hat-stiffened panel, not really a sandwich. I've seen hat-stiffened panels analyzed a few different ways: Beam-stiffened plates, solid-modeled, or sandwich panel with different panel regions...generally in this last one, you can do the entire panel as "sandwich" and make the middle-most layer of the monolith behave as your "core". If you do this last method, you better understand what your pre- and post-processor are showing you. In the first method, you better understand how to convert a hat-stiffener into a homogeneous beam.

 

[airmail]

Well, I'm trying to do a hand analysis, but I don't know how to manage geometry and properties of the cores. Core of 25 means a core which height is 25mm (7--> 7mm). The panel is simply supported.

Actually, it is one sandwich panel where some areas have a core of 25mm and others 7mm.

Thank you again.

 

[GBor]

Much more complicated problem by hand. I suggest you look into an international symposium on sandwich panels that is conducted every other year, I think. They generally have some minutes published (a couple of books each symposium) which includes various theories on sandwich panel analysis. The equations are long, nasty, and anything but straight-forward.

You can usually still simplify it with the beam stiffened plate concept, but you better understand what you are doing...I would suggest trying to make this simplification without someone that knows what they are doing.