topic PU Foam in FUSION 360 Material Database in Fusion Design, Validate & Document Forum

PU Foam in FUSION 360 Material Database

jsLZWXV — Sat, 15 May 2021 08:14:19 GMT

I have set-up a static stress simulation with a piece of PU foam and a glass ball on top. Trying to solve the simulation I get the message:

"Error: Some components are using a material with invalid properties.
Click here to select 'Study Materials' to set a material."

Clicking on it I an pop up opens where PU foam is marked with a yellow triangle with exclamation mark, see attached screenshot (forum 1). Clicking on "PROPERTIES" I found the second pop up (forum 2), some values are red, but I can't change it.

How to get that PU foam (or other flexible materials) running? In addition: How to get other flexible materials into the data base?

Thanks !

Re: PU Foam in FUSION 360 Material Database

Austroanglo — Tue, 06 May 2025 07:16:57 GMT

did you ever figure this out? having the same problem..

Cheers,

Mark

Re: PU Foam in FUSION 360 Material Database

jsLZWXV — Tue, 06 May 2025 07:26:45 GMT

Sorry, no.

Re: PU Foam in FUSION 360 Material Database

TheCADWhisperer — Tue, 06 May 2025 11:54:19 GMT

@Austroanglo

@jsLZWXV

Linear static stress analysis is limited to rigid materials, not flexible materials, not brittle materials.

Re: PU Foam in FUSION 360 Material Database

henderh — Wed, 07 May 2025 19:32:26 GMT

Hi @jsLZWXV,

The reason the material is flagged as invalid is because the Young's Modulus value is zero (i.e. the stiffness is infinitely flexible). I don't see this material in the out of the box Fusion material libraries, so I cannot comment on the reason it should be missing. The PU foam in the Fusion material library's Plastics category doesn't have sufficient properties for simulation as well:

I agree with @TheCADWhisperer, a linear static stress solver isn't able to provide the results you're after if you are seeking an accurate simulation of a material that behaves nonlinearly with the applied load(s).

In order to simulate the foam's nonlinear properties, a nonlinear stress-strain curve will need to be provided in the material definition (a few examples are provided in Fusion Nonlinear Material Library).

Help page for this procedure:

https://help.autodesk.com/view/fusion360/ENU/?guid=SIM-ADD-CUSTOM-MATERIAL-TASK

If the simulation is to simply rest a solid sphere on a block of foam and check the steady=state deformation, the deformation will be considered large and a nonlinear static stress study type will need to be used, or a quasi-static event simulation could also provide results.

Hope this helps! Please let us know if you have any additional questions, comments, or suggestions.

Best regards,