Error "Global mass matrix is singular" when choosing Transient fidelity

[Hossein Mohammadi H]

I am trying to do a 2D dynamic implicit simulation and I have defined density for all parts in my model, except one part which is discrete rigid and I defined a reference point on it and I gave it an inertia. My model works when I use Moderate dissipation or Quasi-static options in step, while when I change it to Transient fidelity it gives me the following error:
"Global mass matrix is singular. Please specify proper material densities, concentrated masses and rotary inertias, or nonstructural mass to fix the mass matrix. As a workaround, *dynamic, singular mass=warning can be used."
If the problem is mass or density, why does it work in moderate dissipation? Do you know how I can resolve this problem?
Thank you for your help in advance,
Hossein Mohammadi

 

[FEA way]

Apart from inertia, try specifying mass for this rigid body’s reference point.

 

[Hossein Mohammadi H]

How should I specify mass apart from inertia? I created a Point mass/inertia using Special->Inertia->create and I could not find any mass apart from that.

 

[FEA way]

I was thinking about Engineering Features —> Inertias —> Point mass/inertia. There you can specify both mass and rotary inertia.

 

[Hossein Mohammadi H]

It is the same thing that I have done. I tried giving both mass and rotary inertia to my reference point and it does not work. However, as I mentioned before, it works when I choose moderate dissipation, but not in transient fidelity!