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Crushable foam

Posted Apr 20, 2012, 8:03 a.m. EDT Structural Mechanics Version 4.2a 3 Replies

Massimo Bechis
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Hi,
I have to model an impact attenuator made of a material that has a foam behavior. The material has been fully characterized with compression tests, which means that stress-strain curve is available.
In the past I modeled the same material in ABAQUS using the “crushable-foam” constitutive model. Now, within COMSOL’s Structural Mechanics Module, I wonder what is the best option between Hyperelastic or Plastic behavior.
Have anyone implemented a similar material in COMSOL and willing to share some tips?

Thank you.
3 Replies Last Post Apr 23, 2012, 8:21 a.m. EDT
Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago Apr 20, 2012, 6:09 p.m. EDT
If the crushable foam is used for impact attenuation then it is mostly likely loaded beyond its elastic limit. Elastic-plastic material is a better choice from the two you mentioned, but it is still not a good one. The yield behavior is pressure independent and the plastic flow is incompressible. Both do not match crushable foam behavior. The Cam-Clay material model in the geomechanics module is probably a little more suitable. There is always of course the option of directly implementing a suitable foam material model yourself in COMSOL.

Nagi Elabbasi
Veryst Engineering
If the crushable foam is used for impact attenuation then it is mostly likely loaded beyond its elastic limit. Elastic-plastic material is a better choice from the two you mentioned, but it is still not a good one. The yield behavior is pressure independent and the plastic flow is incompressible. Both do not match crushable foam behavior. The Cam-Clay material model in the geomechanics module is probably a little more suitable. There is always of course the option of directly implementing a suitable foam material model yourself in COMSOL. Nagi Elabbasi Veryst Engineering
Massimo Bechis
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Posted: 1 decade ago Apr 23, 2012, 2:48 a.m. EDT
Thank you.
Unfortunately I don't have the geomechanics module but only the structural mechanics and I don't know yet how to implement a foam material by myself (any tips about this?). I'll work with elastoplastic material for the moment.
May I suggest to implement additional material models in the future versions of COMSOL?
Regards

Massimo
Thank you. Unfortunately I don't have the geomechanics module but only the structural mechanics and I don't know yet how to implement a foam material by myself (any tips about this?). I'll work with elastoplastic material for the moment. May I suggest to implement additional material models in the future versions of COMSOL? Regards Massimo
Nagi Elabbasi Facebook Reality Labs
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Posted: 1 decade ago Apr 23, 2012, 8:21 a.m. EDT
There is a good example in the COMSOL model gallery called “Viscoplastic Creep in Solder Joints” that shows how to implement material models in COMSOL, in this case the Anand model. It’s a good idea to suggest new material models to COMSOL for their future releases. You should do that by contacting Support.

Nagi Elabbasi
Veryst Engineering
There is a good example in the COMSOL model gallery called “Viscoplastic Creep in Solder Joints” that shows how to implement material models in COMSOL, in this case the Anand model. It’s a good idea to suggest new material models to COMSOL for their future releases. You should do that by contacting Support. Nagi Elabbasi Veryst Engineering

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