FUSION 360 Simulation Solve error

[Anonymous]

Hello Having trouble running a static simulation on a assemby.  I did two similiar simulations two weeks ago and they ran fine. I noticed the contact menu and options format has changed since that time.  It used to allow seperation and sliding but now it looks like you have to pick on or the other? Not sure if that is part of the issue. I could aslo post the similiar models that have successfully run fine prior to the changes.

This is a good method for determining pin bending stress which is somewhat complicated and should not be ignored.

The error messages are below. I noticed someone else had the "Model contains 1 fully unconstrained group(s) in load case" on a post from 02_24_2016 but it was a different issue. 

Thank you for any attention or replys

Summary:
Error: Solver Error
Error: An error occurred while solving the model.

Mesh Details:
39598 Tetrahedra : 100.0% of elements (100.0% of volume)
Face Angle min: 14.9, max : 146
Dihedral Angle min: 17.3, max : 150
Worst shape ratio : 6.71 on element 4733
Worst aspect ratio : 4.08 on element 5205, shortest edge: 0.00212, longest : 0.0356
Lowest collapse ratio : 0.231 on element 4733
Worst Jacobian ratio : 1 on element 1
Base mesh: 62134 nodes, 39598 elements
Solver mesh: 62134 nodes, 39598 elements
Job has finished with errors. Receiving results.
Error: Solver Error
Error: An error occurred while solving the model.

Warning: Warning: Model contains 1 fully unconstrained group(s) in load case "Load Case:1".

Click here to select 'DOF View' to inspect.

Click here to select 'Manual Contact'.

Click here to select 'Automatic Contacts'.

[Anonymous]

Note I just ran one of the similiar models that ran sucessfully two weeks ago.  I cloned the study and only changed the value of the load.

So it looks like something is wrong with fusion not my models. 

Thanks for any help figuring this out

[Andrew.Sartorelli · Accepted solution]

Hi @Anonymous,

There were a few changes to the FEA solver and environment in early November when we switched to Autodesk Nastran for the solver, as well as introduced a few new solution types such as Non-linear Static and Shape Optimization. I suspect this is the change that may have affected your models. We did try to account for all circumstances to convert models moving from the old technology to the new technology, but it looks like we missed a few changes. Sorry about that. 

I've had a chance to take a look at your model and the good news is that some of these enhancements to the simulation environment in Fusion 360 will make things better for you. Here are a few of my suggestions.

• Change from a linear static analysis to a non-linear static analysis
• Change the contacts from separation to sliding, this will be the same as "Separation, Sliding" in the previous version.
• Add local mesh control (under manager on ribbon) to the pin's contact surface and associated contact surfaces on the other parts
  • The mesh right now is fairly coarse in the contact region, which leads to faceting on the contact surfaces. Because in FEA we need to descritize curved surfaces into polygons defined by the edges of our finite elements, we need to check to make sure the nodes are overlapping or penetrating as we try to approximate a circle. Generally as we refine the mesh in this circular region it will become a closer approximation of a circle.

Here is an example of this problem with faceting in circular regions, notice the elements from the pin penetrating into the elements on the elbow.

Best Regards,

Andrew

[Anonymous]

Hello Andrew 

Thanks for the reply. For some strange reason the model ran on Sunday. After not working on Friday of Saturday. Not sure why.

Are the FEA mesh refinements you mentioned in the latest version of Fusion 360? Or in profesional inventor FEA, which I do not have.  If they are in a later version of fusion 360 then i will need to take the time to download it.

Thanks

Tim

[Andrew.Sartorelli]

Hi @Anonymous,

Local mesh control was introduced in early November, because you were seeing some of the update Nastran settings than I would say that you are already on this version.

Regards,

Andrew

[Anonymous]

Hello

I believe the non linear option is only with Fusion 360 ultimate. With the product Design suite we get Fusion 360 but not the ultimate.  ?? I think. As no options under preferences for non linear.

Tim S

[Anonymous]

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Hello I do reply here because I got the same problem than Tschrader two years ago.I did a FEA that worked correctly and later I just copied the same study and changed the value for the force and the solver doesnt work anymore.I have to add that I was working in the cloud but my credits are finish.Anyway I have tried locally and in the cloud and locally from my colleagues and it doesnt work anymore.Moreover the rest of the documents that I have been working with before doesnt work either.

Hier bellow the messages:

Summary:
Error: Solver Error
Error: An error occurred while solving the model.

Mesh Details:
9452 T : 100.0% of elements (100.0% of volume)
Face Angle min: 3.37, max : 172
Dihedral Angle min: 1.91, max : 175
Worst shape ratio : 60.7 on element 7315
Worst aspect ratio : 16.9 on element 5876, shortest edge: 2.14e-05, longest : 0.00491
Lowest collapse ratio : 0.0318 on element 7315
Worst Jacobian ratio : 2.74 on element 7355
Base mesh: 18020 nodes, 9452 elements
Solver mesh: 18020 nodes, 9452 elements
Job has finished with errors. Receiving results.
Error: Solver Error
Error: An error occurred while solving the model.

I did tried with cleaning the user cache data but it didnt work either.I am not sure which would be the problem but I am having as well problem to open some documents like is not founding the last version((this already before cleaning the cache)