Same simulation diffrent results in Fusion 360 and in-cad Nastran

[d.boshnjakovski]

I made simulation with same settings, same material and get two totaly different results. Fusion smash the part and In-cad Nastran show deformation of few mm.

[TheCADWhisperer]

Can you File>Export and then Attach your *.f3d file here?

[d.boshnjakovski]

Sorry I cannot do that because of NDA. Here are some steps what I did. Inventor simulation failed to complete the simulation because of large displacement. Transfer the simulation in In-cad Nastran and get result in mm. Wanted to see what will be the result in Fusion 360. So I import the Inventor assembly file in Fusion 360 and convert the file in fusion extension. First run the simulation as assembly. When find totally different results (too big deformation) I was thinking that contacts are not OK and isolate only one part that has the biggest displacement. Run the part simulation parallel in Fusion 360 and in-cad nastran. The result is with same geometry, dimensions, material and settings constrain and force, but different results.

I try to make example simulation, but the difference in displacement is less than half mm. For me that is affordable mistake.

[shigeaki.k]

Hello @d.boshnjakovski,

are you happy to share the model with us via a case made for you in Autodesk Account? 

Regards,

Shigeaki K.

[Anonymous]

Did you run the fusion 360 simulation as non-linear?

[d.boshnjakovski]

No, simulation was linear in both software’s. I was trying to see if the materials would transfer from software to software.

[shigeaki.k]

Hello @d.boshnjakovski,

could you elaborate further on the workflow you took to "...to see if the materials would transfer from software to software.". To import the model into Fusion 360, you would need to save the model in a neutral format such as STEP. Not all the material properties are saved with the neutral format model. Hence, you will need to select the proper material or input the material properties.

I ran a simple analysis in both Inventor and Fusion 360 Sim. with the material properties, constraints and load and obtained similar results as shown below.

Could you check if the material properties and the other setups are similar between Fusion 360 and Nastran In-CAD analysis?

Regards,

Shigeaki K.

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[d.boshnjakovski]

Hello @shigeaki.k,

In the attachment you can find my results form both In-CAD Nastran and Fusion 360. As material I use rubber butyl, and for force 1500 N in -Z direction. Constrain the part at the bottom and select fixed. The difference is almost 0.812 MPa and the displacement is the same (with acceptable error of 0,03 mm). I chose the material from Autodesk material library . It would be great for Idea where we can define the material at one place and automatically can be accepted/transferred at any Autodesk software with the part/assembly.

In the latest version of fusion 360 you can upload the file directly in the application. You don't need step or iges any more.

Thanks for the idea how to present the simulation with a simple example.

[d.boshnjakovski]

Also IPT and F3D file.

Dimension of the cube is 3 x 3 x 3 in