Simulation of the Rotating Disc Under the Gravity Load in Abaqus?

Hello everybody

I'm trying to simulate the rotating disc under the gravity load.

The goal of this simulation is, get to the displacement frequency of this system (Center point of the disc).

Part module:

Created part shown in image (1):

Image (1)

This part is: 3D ,Deformable ,Solid.

Dimension: meter.

Property module:

Material is:

Steel (Stainless Steel Grade 304)

Mass Density: 7900

Young's module: 193 Gpa (193E9 pa)

Poisson's Ratio: 0.265

Expansion Coeff alpha: 1.7E-005

*Plastic:--------Yield Stress-------Plastic Strain
1)-----------------176E6------------------0
2)-----------------350E6------------------0.1
3)-----------------451E6------------------0.2
4)-----------------490E6------------------0.3
5)-----------------540E6------------------0.4
6)-----------------555E6------------------0.5
7)-----------------568E6------------------0.6
8)-----------------555E6------------------0.7
9)-----------------490E6------------------0.8
10)----------------411E6------------------0.82

-------------------Table (1)

Section is: Solid, Homogeneous.

*This Data (Plastic) is not accurate.

Assembly module:

This Part (Show in image 1) made from merge of the Disc and Shaft.

Also there is a Cylindrical coordinate axis and 2 Reference Points.
Image (2)

Step module:

There is 2 Dynamic, Explicit Steps in this simulation:

The first step is a dummy step and just for model stability. Cause of existing this step is:

Model get under the pure gravity load (in this step there is no Rotation).

Value of this step is: 0.2

The second step have both Rotation and Gravity.

Value of this step is: 10

Interaction module:

There is 2 Rigid Body constrains in this model and they're Region type is Pin (nodes), like image (3):

Image (3)

With getting the highlighted area in image (3) rigid body, I assumed that area is Virtual Bearing.

Load module:

Gravity load configuration is in the image (4):
Image (4)

Gravity load did not apply to the rigid body areas (Virtual Bearings).

The 2 boundary conditions configuration is:
Image (5)

Image (6)

Also the amplitude for modified step is:

Image (7)

Mesh module:

All elements type is:C3D8R: An 8-node linear brick, reduced integration, hourglass control.

Image (8)

Results:

After a while, GR monitor show like image (9) and it seems abaqus can't get to the convergence and stick in the total time 8.2 and I don't know why something like this happening?!

Image (9)

But when using double precision and nodal output precision (Full), model did not get stick on the 8.2 total time.
Warning of GR monitor is:

2 nodes lie on the axis of their cylindrical or spherical transformation systems. The local coordinate systems at these nodes are not well-defined. The nodes have been identified in node set WarnNodeCylTransSys.

Output request e is not available in a nonlinear step -- le (log strain) will be output instead.

Output request damageshr is not available for the material for element type c3d8r

Output request peeqvavg is not available for element type c3d8r

Output request pevavg is not available for element type c3d8r

Output request shrratio is not available for the material for element type c3d8r

Output request svavg is not available for element type c3d8r

Output request sth is not available for element type c3d8r

Output request e is not available in a nonlinear step -- le (log strain) will be output instead.

Output request damageshr is not available for the material for element type c3d8r

Output request peeqvavg is not available for element type c3d8r

Output request pevavg is not available for element type c3d8r

Output request shrratio is not available for the material for element type c3d8r

Output request svavg is not available for element type c3d8r

Output request sth is not available for element type c3d8r

There are 17 warning messages in the data (.dat) file. Please check the data file for possible errors in the input file.

All nodal degrees of freedom are constrained by a rigid body for deformable elements listed below. To reduce computational expense, convert these elements to rigid. Refer to the status file for further details.

Visualization module:

I make the interval value 20 for the gravity step and 10000 for the rotating step to get the more accurate outputs.

In frame of 8000 model body get like image (10):
Image (10)

As you can see we have deformation after the rigid body constraint area.

Also whole of the body except the rigid body areas get smaller, see image (11):
Image (11)

To get the wanted frequency (displacement) I get to "XY data from ODB field output" and pick the "unique Nodal" and mark the "UT" then choose the center node of the disc, as shown in the image (12).
Image (12)

The graph came from this configuration is image (13):
Image (13)

Now after all of this explanation, is there anybody know what should I do to get the right answer?

Because I think after a while (maybe 1.5 sec) graph should have sine displacement, like image (14):

Image (14)

Thanks.

Yassou.