Modal and Inertia Relief Analysis problem does not move - what went wrong?
Hi all. Running v2025 have gone through the online example:
Altair Course: Getting Started with HyperMesh v2024
which does a inertial relief and modal analysis on a 3D satellite model. To try it myself, I have built a very simple 1-D CBEAM model of a wing with a 16 element component mesh and RBE2 fishbones simply for visiblity that are connected to the beam as "independent nodes" and connected to nodes I made at the leading and trailing edge as "dependent nodes"
There is a distributed force at all 16 nodes of the CBEAM model, but not at the root, where I have a STRUCT-1 constraint in all 6 DOF, expecting that to be similar to a cantilever environment. I followed every step from the Altair course satellite example including setting the PBEAM properties, which is correctly set to aluminum material properties and defining an EIGRL Load step input with two Load Step subcases: linear stress relief and modal analysis - all just like the satellite example.
The solver runs with no errors, but when I bring in the solution, the beam appears not to move.
As you can see from the Model menu, there are only 17 forces: 16 along the flexible axis and one at the root.
Any hints of what I did wrong?
could you share the .fem and the .out file?
Is there any warning or message into the .out file maybe?
Thank you, Adriano_Koga!
Now that I look at it, the *.out file does have some warnings & errors but I am a BRAND NEW beginner, so I do not understand exactly what my options are.
For instance, there are errors: "*** WARNING 1935: The density of material 1 is zero. "
and "All the material density are zero and there is
no mass element or external mass matrix."
But this was on purpose. I am working from an old classroom example. The professor had instructed, "Hint: Use the NSM and NSI fields in the PBEAM card for this, leave the RHO density field in the MAT1 material card equal to zero or empty." So I left rho blank in the material card, instead setting NSM in the to be the mass per unit length and computed the NSI. Is that not the same as using the Rho field of the Material?
Then the information: *** INFORMATION # 815
The total number of rigid elements, whose rotational dependent d.o.f.
are removed because there is no need to constrain those d.o.f., is 34.
I think this is as I designed. The 34 are the rigid fishbones (17 per side) that should just move along with the wing beam bending motion, so they should not be constrained.
Just for fun, I tried deviating from the professor's tip and entered the rho for this Al (2712 kg/m^3) and ran it with that parameter not zeroed out.
It gave error: "MATTi data present, but there is no TABLEMi"
What? I tried googling that error, but it makes no sense. There seems to me an infinite combination of possible datum in HyperMesh - so confusing!
Thank you in advance for any help.
-Emmie