FINALLY, chassis design almost finished...

[zeropointbug]

I haven't been on these forums for over a month now, i am just updating that i have pretty well finished designing my chassis (chassis brace).

Serum, I have Alibre Design Professional, and one of the add-on programs is ALGOR design check. It's a static, linear material stress model simulation, and if i am reading the results properly; at 360Newtons(800 lbs) of force on the upper-front mounting point, this thing doesn't even budge. You can visually see where the forces are transferred and everything.

Anyways, people here that know anything about the energies, and forces involved with an RC crash (e-maxx size); i need to know the absolute minimum amount of force that a chassis should be able withstand (ultimate strength-wise). I think i should be able to shell sections on it after all.

Here is a pic.. sorry for crappy size

[MetalMan]

Pardon my ignorance, but which vehicle is this for?

[zeropointbug]

oh sorry, i did type emaxx in there, i guess not plain enough.

It may not look like much with one brace on it's own, but a motor mount/gear mount, shaft bearing floater, bottom chassis plate, upper connecting plates, and ESC mount/heatsink (Quark 125) are yet to be made. So sit tight, it's coming! One major feature of it is the extreme rigidity.

Alibre CAD tells me one brace weights in at 94 grams, i am aiming to cut that down to AT LEAST 60 grams. That's 6061-T6, i might just go ahead and use 7075-T6 alloy, it's almost twice as strong, and hard.

Cheers,

zero

[BrianG]

It's cool that you can model stress factor. Don't forget stresses on different axis' - because not all crashes are directly head-on (I'm thinking when the truck does cartwheels).

[zeropointbug]

you bet! I can do any axis force direction you can think of. I have been playing around and when i apply a 4000 (1800Newton) force head on, i only get up to 60N/m^2 of stress on the thing. I don't know about you, but that seems very low. I did, however design it so it quickly distributes the load away.

I will have pics soon of a legit stress simulation.

zero

[jnev]

Very cool. That is aneat program as well. That sia ncie design and shoudl hold up well.

Good Job!!

[BrianG]

You do realize that once you get the design actually made, you're gonna have to test each stress scenario in real life to see how accurate your modeling is. Of course, that might be a tad expensive. :dft012: :005:

[zeropointbug]

Thanks 'RC'

BTW, the taller section is for the motor mount, and where you slip the spur gear in and out. The beefy section is where the shaft bearing mount attaches; the shaft extends from there to the tall vertical section.

[BP-Revo]

Looks good. Makes me want to get my hands on something like this and design a rediculously strong X-Brace for the G2 and G2R chasses.

The design of the X-Brace is fine for the G2, but on the G2R the load is applied a little differently to the brace... I'm wondering if I could just design a brace to better distribute the load...and maybe more.

Edit: Oh, you may also want to factor in what stressed may be applied during the crash by the inertia of the motor (motor trying to rip itself off the chassis) and stuff like that.

[zeropointbug]

yah, that's one thing that I don't really like about the Gorillamaxx chassis', they look weak to me, has anyone had one break on you?
Also, if someone has one of the emaxx Gorillamaxx brace on hand, do you think you could measure the weight for me? Preferably with a digital scale.

BP-revo, if you really were willing to, i could design a brace for you? Then you could just take it to a local machine shop...

BrianG, lol, yah right! That's the thing, im sure you can make a better design with these programs, BUT noting compares with real world scenarios, and accuracy :005: !!SNAP!!

Zero

[BP-Revo]

Nah, I wouldn't want you to go through the trouble. The design isn't that bad, it just needs a cross brace or two between each "arm" on the brace and the tranny mount area needs to be a little beefier, since all the stress is placed on the narrow point.