Exporting Panel Properties Using Offsets

[James]

In response to a question submitted via email:
 
Do you have a methodology via which we can put the grids at the true outer surface of the wing and use offsets to put the shell material in the correct location?

Not for stiffened panels, only for solid laminate and sandwich panels.  There is no way to modify the output NA of stiffened panels in HyperSizer.  HyperSizer assumes the NA is at the midplane of the top facesheet, this is where we assume the grids are modeled at in your FEM, so this is the location HyperSizer exports the ABD matrix from.  This can not be changed using offsets.  The reason we cannot change this location is simple, you can not apply offsets to PSHELLs and MAT2s.  The only way to apply offsets would be to apply them directly to the CQUAD4 elements.  HyperSizer does not have the capability to modify the CQUAD4 elements, only the property cards (ref .PM1 file).

Since the stiffened panel properties are exported at the midplane of the top facesheet, for stiffened panels with thin facesheets, this may not be a huge problem since the difference will be only (1/2 tf).

You may use the offsets in this way to export LAMINATE data at any location (solid laminates, honeycomb/foam sandwiches).  Since you can apply offsets to PCOMPs, HyperSizer will easily export the laminate data with the appropriate offset.  There is a ppt on the website which will show you the notation of HyperSizer's offsets for laminates (NASTRAN_Imported_and_Exported_Data_Including_PCOMP_Laminates_2008-09-08: ref slides 31 and 32).  Read it carefully because it maybe confusing the first go around.

(***Note: To apply offsets to a laminate or sandwich you must make sure you are exporting to PCOMPs and MAT8s, activate this option on the 'Analysis Defaults Tab' of the Project Setup Form.)