Any one try foam-filling their chassis?

[AK Maniak]

did you seriously just "bump" a 5 year old thread?

 

[habitatguy187]

And?

 

[PotatoFlakeSTi]

And?

I think what Mr. AK meant was... "Why?"

/sage

 

[gixrman]

I've used it for composite parts and it does add structual support. At what point does it matter, and worth the effort? Hmmmmm........
You can get it in 2,4,6,8 pound densities (and there may be more) which one is the most effective, dont know.
Heres a supplier that i've used.
AeroMarine Products - Polyurethane Pour Foam for Insulation and Flotation

it is an interesting concept, better than spot welding the seams?
But 'd over bringing back a 6yr old thread. How many of the original posters are still around?

 

[Timechg]

I thought I would chime in on bjones comments about Elastic modulus and torsion etc.

1) Elastic modulus does not really pertain to foams, you cannot perform any tensile test for foams (usually only compressive tests and the modulus would be very very low).

2) Elastic modulus assumes the material is isotropic or they usually have the same material properties in all directions. Foam is generally anisotropic (different material properties in different directions, not predictable) sometimes with a negative Poisson's ratio with a lot of volumetric space/pores.

3) Torsion can be described as rotating shear in which inertia is calculated for the object that is rotating (within it self). Inertia can be described as the resistance to rotate. If you have an open tube and a closed tube (cylinder) and you try to create torsion, the closed tube will have the highest resistance to torsion (given that they are made out of the same material and have the same rotating load).

So what does this all mean for foam in the chassis?

Increases damper and rigidity (I wouldn't know how much, only if this foam is really able to dry completely solid within the chassis without any gaps). Increase the inertia for any give cross section reducing torsion on a member in the chassis (perhaps additive for all members that are foamed in the chassis).

A great example of foam in a chassis is human bones. They have a hard shell on the outside (cortical bone) and the inner part is a foam known as cancellous bone. The cortical bone is analogous to steel perhaps and the cancellous can be referenced to foam. Cortical bone has a higher elastic modulus ~10 times that of cancellous bone (this has a low modulus that is compressive), but together they are able to resist greater loads than if they were separated. They increase compressive load bearing, increase stiffness and adds to the moment of inertia/resistance to rotate.

I think it's a great idea, but of course it is always difficult to really come up with 'numbers' that support this in a certain car or any. Results are most likely qualitative, but I am sure that adding foam to the chassis would help stiffen things up.


---I didn't realize I was writing on a super old thread...