Buckling of Honeycomb Panels with Directional Transverse Shear Flexibility

[HyperSizer User]

After performing honeycomb sandwich panel buckling analysis I have noticed that the directional difference in the transverse stiffness constant is not taken into account (it is averaged). In the report you state that for sandwich (honeycomb or foam) that “These types of panels exhibit similar relative transverse stiffnesses in the x and y direction”. For foam core I agree but for honeycomb I disagree.

Is there any way that the foam and honeycomb analysis can be split so that the transverse shear stiffness constant is averaged for foam only but is directional for honeycomb?

[Phil]

I think the reason that we use an averaged TSF is that in general we assume that honeycomb panels will have biaxial loads and the buckling calculations don't distinguish between Nx and Ny loads, they simply use the biaxial load state when calculating the buckling critical load.

I suppose what we could do is calculate TSF in the x direction and TSF in the y direction and then weight them by the magnitude of compressive load.

Something like:

TSF_used = Nx / (Nx+Ny) * TSFx + Ny / (Nx+Ny) * TSFy

So that way for pure Nx loads, TSF = TSFx and for pure Ny loads, TSF= TSFy

I could see implementing something like this, what do you think?