Reaction Moments on Grille Vane
Reaction Moments on Grille Vane
(OP)
Hello!
I'm trying to determine the torque required to hold a grille vane in position when wind at a certain velocity is blowing against it.
I obtained the pressure profiles on the vane from a CFD analysis, mapped those results onto an FEA mesh, and solved the analysis. I constrained one end of the shaft (about the axis of which the vane rotates - the Z axis) completely, and constrained the other end in plane, i.e., Tx, Ty, Tz, Rx, Ry.
Firstly, is this the right set of constraints for a case such as this? Secondly, how do I obtain the reaction moments about the Z axis which gives me the torque required to hold the vane in place?
I tried the "Freebody Display" but I wasn't able to get the reaction moments from it.
I'm trying to determine the torque required to hold a grille vane in position when wind at a certain velocity is blowing against it.
I obtained the pressure profiles on the vane from a CFD analysis, mapped those results onto an FEA mesh, and solved the analysis. I constrained one end of the shaft (about the axis of which the vane rotates - the Z axis) completely, and constrained the other end in plane, i.e., Tx, Ty, Tz, Rx, Ry.
Firstly, is this the right set of constraints for a case such as this? Secondly, how do I obtain the reaction moments about the Z axis which gives me the torque required to hold the vane in place?
I tried the "Freebody Display" but I wasn't able to get the reaction moments from it.





RE: Reaction Moments on Grille Vane
don't know why Mz isn't showing in free-body display ... check that the "show moments" box is ticked.
if not, print the output and look it up in the f06 file.
RE: Reaction Moments on Grille Vane
I even simplified the model to a simple rectangular plate with 2 cylindrical pivots on the opposite faces, fixed the pivots, applied opposing forces on the top and bottom edges of the plate, and solved the analysis. I just couldn't figure out a way to obtain the reaction moments in Femap.
This is a simple problem in which the reaction moments can be calculated manually, but there's gotta be a way to get calculate them for more complicated problems analytically. I know how to get the moments in ANSYS, but I can't use that at work.
Blas, anyone else, any ideas?
RE: Reaction Moments on Grille Vane
what does your deflected shape look like ?
RE: Reaction Moments on Grille Vane
All I had to do was create a node along the axis of the shaft on each end, a little outside the outer shaft surfaces, and connect each node to all the nodes on the outer surfaces using rigid elements, and then constrain those two nodes appropriately, i.e., one node completely, and the other about Tx, Ty, Tz, Rx, Ry. I can now see the reaction moment about the Z axis on the latter node when I do the freebody display.
Thanks for the help though!
RE: Reaction Moments on Grille Vane
if you constrain each node on a tube surface as fully pinned, you are restaining the three moments as well, only you'd need to do some math to extract the results.
RE: Reaction Moments on Grille Vane
RE: Reaction Moments on Grille Vane