Engineering & Analysis Methods > Miscellaneous Analysis & Methods

Use Non-Structural Core In HyperSizer

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Phil:
We have skin-stringer concepts in HyperSizer natively.  You can size and analyze a hat very effectively in HyperSizer.  We don't have a filled hat, but since your core is non-structural, that would not be a concern.  You could use the same shell model to size the hats, you don't need to model the stiffeners discretly.  Go to the Basic user manual and look at the first tutorial example for how to build a hat section in HyperSizer.   

One major concern I have is that the load paths for a skin-stringer structure will be very different than they will be for a honeycomb sandwich.  The A11/A22 ratio will be high, but the D11/D22 ratio will be very high for the skin-stringer, maybe as much as 20-1.  The panel essentially has no bending stiffness in the transverse direction.  If you use FEA loads that were developed using honeycomb panels which are roughly the same stiffness in the two directions, then the hat would have to size up tremendously to take the high transverse loads.

In order to size a skin-stringer properly, you really need to iterate the FEM and put the skin-stringer ABD matrix into the FEM so that the load paths re-distribute.  Basically, your Y direction loads, Ny, My and Qy should drop way off when you go to a skin-stringer design and all loads will be primarly carried in the X direction.

Phil

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