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Author Topic: Orthogrid object loads have no Ny,My,Mxy in Webs  (Read 23786 times)

Kanit_Cor

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Orthogrid object loads have no Ny,My,Mxy in Webs
« on: July 30, 2008, 07:30:25 AM »
After entering user loads in NX,Ny,Nxy,Mx,My,Mxy,Qx,Qy, and sucessfully analyzing a orthogrid component, there are zero values for the Object Loads Ny,My,Mxy in the 0Web and 90Web Ribs.  This is not expected since the ribs should see a non-zero value of load for Ny,My,Mxy under load in the same type.

The same problem occurs under mechanical load set loading.

I was wondering if anyone else has encountered this problem and has found a solution to it?




Phil

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Re: Orthogrid object loads have no Ny,My,Mxy in Webs
« Reply #1 on: July 30, 2008, 08:35:14 AM »
The object loads for the orthogrid ribs (or for any object), are the loads with respect to the object coordinate system, not the panel coordinate system.  For any web, the X direction is along the rib, parallel to the facesheet and the Y direction is across the web, perpendicular to the facesheet (in the panel Z direction). 

The assumption that HyperSizer makes for the ribs is that they are free to expand in the Y direction, therefore the Ny load on the web will always be zero.   The same argument holds true for My loading, since the lower edge of the web is free, there will be no My driver.

The Nxy loading for a web object will come from the Qx and/or Qy loading.  If the Qx load is non-zero, then you should see a corresponding Nxy in the 0 web, and if Qy is non-zero then you should see a corresponding Nxy in the 90 web.

In reality, there will be some corner effects where the webs come together which will be missed, however, these effects should be very small compared to the primary loading.

I hope this helps.
Phil