Reading Axial loads from a FEM Model with gravity load

[brailos]

Hello,

I have stumbled on a issue , regarding the design of sandwich honeycomb panel structures.

I have no problems in designing and making the analysis for rectangular plates , as for Bruhn and BDMs are more then enough and clear, but as long as your inputs are known.
My structure is a stowage made of several honeycomb sandwich plates subjected to gravity loads.
I have prepared all the excel sheets and analysis procedures according to Bruhn but i need somehow to estimate the axial ,shear and bending loads that the gravity load would induce in my structure.
I was thinking of making a Fem model in Nastran with all the panels approximated more or less as rectangular panels and output the Grid Point Forces in the delimiting nodes of every panel thus obtaining the axial forces(not tested yet , just thinking of it).
Also i was thinking of making every panel as a shell CQUAD8 element and reading the forces in the nodes.

I really need some ideas on this matter because i don't really see a correct way to transform the gravity load into loads that i can input in my excel sheets.
Someone else must have had this problem before me, how is it done?

Thank you in advance. Any idea is welcomed, although i hope someone here knows a practical method.


Best regards.

 

[jean15paul]

Creating a FEM model and applying the gravity load seems like a good approach, but make sure you correctly account for the stiffness. If they stiffness aren't correct it will change how the load get distributed through the structure. You said "sandwich honeycomb panel structures". Do they have composite facesheets or metal facesheets? If they are composite, are they quasi-isotropic? Make sure you cosider the directional properties. You will probably need to model them with PCOMP properties to make sure you capture the effect of the various layers.