Doubt about Impact atenuator.

[tmattosj]

Hello guys, i`m participating of FSAE Brazil this year. I want to know what kinds of materials are usually applied in the composition of the front impact attenuator and why (wheight, resistance...). Best regards.

[tmattosj]

Hello guys, i`m participating of FSAE Brazil this year. I want to know what kinds of materials are usually applied in the composition of the front impact attenuator and why (wheight, resistance...). Best regards.

[exFSAE]

Aluminum honeycomb, expanding foam, insulating foam, aluminum tube, steel tube, chicken wire, green bean cans, beer cans, fiberglass, carbon fiber, and whatever other crap is laying around.

Its not something you're going to be able to predict. Just build a bunch of different crap and drop weights on it, see which ones actually work (if any).

[screwdriver]

AL-Honeycomb(heavy), Styrofoam (light) and various composites(even lighter).
That's what I've seen on the cars so far. You're best off looking at photos.
If you're looking for detailed recommendations, search the forum, there are some threads with recommendations.

Besides why are you in doubt about yours? What do you use or what do you plan to use? If you let us in on some details, we may be able to provide better feedback.

[Fyhr]

We used this foam:

http://automotive.dow.com/materials/products/impaxx/index.htm

It isn't very heavy, however a composite structure wrapping it in some sort of fiber might be made even lighter.

[Nik]

What you want in an impact attenuator material is a nearly uniform crush strength. In other words if you graph a compressive stress vs. displacement curve for the material it should rise quickly to the crush strength and then stay relatively constant for a long displacement. With this kind of material you can fit the most amount of impact energy in the smallest package without exceeding your 20g's.

This year our attenuator is aluminum honeycomb and weighed in at .9 lbs.

Has anyone gotten back there approved impact attenuator data submission yet? I sent in ours on time and all I've gotten back is the confirmation email saying they got it.

[Drew Price]

Depending on your analysis techniques you may also want a material/structure whose energy absorbtion properties are relatively independent of strain rate.

Best,
Drew

[tmattosj]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">honeycomb </div></BLOCKQUOTE>
thanks!

[Drew Price]

Wow.