tug
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| posted on 8/10/10 at 12:35 PM |
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Chassis safety design
Searching didn't help.. Do you guys think about safety when designing a chassis? Not talking about roll over cage because that is easy mode
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But more of front impact crash, or even rear/side crash. Do you implement a crash box?
thanks
[Edited on 8-10-10 by tug]
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Bluemoon
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| posted on 8/10/10 at 12:47 PM |
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Try "saftey" under the chassis section. A few come up. The search is quite rubbish at finding stuff...
Might be worth using Google with
site://www.locostbuilders.co.uk chassis safety
you get loads of hits then
Dan
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Fozzie
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| posted on 8/10/10 at 12:49 PM |
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tug ...when searching......in the search box type %chassis safety% then press the search button .... using the % will bring up quite a lot as it
isn't searching for the specific phrase .....
HTH
Fozzie 
'Racing is Life!...anything before or after is just waiting'....Steve McQueen
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daviep
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| posted on 8/10/10 at 12:54 PM |
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quote:
Originally posted by tug
Do you guys think about safety when designing a chassis? Not talking about roll over cage because that is easy mode .
But more of front impact crash, or even rear/side crash. Do you implement a crash box?
thanks
[Edited on 8-10-10 by tug]
I think you maybe slightly confused, try searching over at volvobuilders.com for more help 
“A truly great library contains something in it to offend everyone.”
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scootz
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| posted on 8/10/10 at 12:55 PM |
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I understand that the space-frame chassis is pretty good for absorbing a frontal impact - but like all things it could undoubtedly be made to be
safer.
I like the raw appeal of the spartan design and I suppose there's even some kind of appeal to it's vulnerability... it all adds to the
sense-of-occasion you get when using your machine and it MAKES you respect it AND the road all the more!
It's Evolution Baby!
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scootz
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| posted on 8/10/10 at 12:56 PM |
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quote:
Originally posted by daviep
I think you maybe slightly confused, try searching over at volvobuilders.com for more help
It's Evolution Baby!
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tug
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| posted on 8/10/10 at 01:23 PM |
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quote:
Originally posted by daviep
I think you maybe slightly confused, try searching over at volvobuilders.com for more help
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Dangle_kt
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| posted on 8/10/10 at 04:48 PM |
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One of the reason I like my kit car is cos I can stick it in much harder than I ever felt safe doing on a bike.
I compare my safety to that, and feel happy.
If I was to compare it to a modern tin top I wouldn't. But I didn;t want that.
I have seen a few kits with side impact sections (rememeber that kit car crisis programme? pretty sure that had them)
I'm not sure that the chassis could be made much safer whilst keeping it cheap and light weight.
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A1
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| posted on 8/10/10 at 05:36 PM |
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having seen some of the crashes people have had, im not sure they really need to be made safer...
obviously, techhnically they could be, but that would mean weight...and as we all know, weight is the enemy
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norfolkluego
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| posted on 8/10/10 at 06:29 PM |
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Weeelll,
I've recently had the (somewhat dubious) honour of testing the strength of a Luego chassis. Got a bit over enthusiastic sprinting at Hethel a
few weeks ago and introduced the car to the tyre wall (and these aren't the sophisticated deep tyre walls that F1 have) at a rather indecent
speed. Verdict - space frame chassis's are VERY strong, I didn't have a scratch, thought me head had come off mind
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MikeR
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| posted on 8/10/10 at 06:43 PM |
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arguably the chassis is too strong then as it should deform to take away some of the impact.
I've added some additional bracing into my chassis around the cockpit but i'm debating adding in another chassis rail in the engine bay.
My solution is to make it a removable brace and remove it for road driving. Hopefully then if i ever crash on the road it will help the engine bay
deform and save me or my passenger. If i ever go on track i can add it and have a stiffer car (hoping the run off areas slow me down enough).
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norfolkluego
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| posted on 8/10/10 at 06:52 PM |
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quote:
Originally posted by MikeR
arguably the chassis is too strong then as it should deform to take away some of the impact.
It did deform but it was a hell of a whack, went in rear first at an angle of about 30 degrees, now got banana shaped wishbones front and rear on the
drivers side and some damage where the rear lower wishbone connects to a chassis member, we're starting to strip it this weekend to see the full
extent, I'll post some pics when we can see the damage. Have to say I was very impressed at how it kept me in one piece. Look at the avatar to
see how close I was to the initial point of impact (rear corner drivers side) and there is zero damage/intrusion into the cockpit at all.
[Edited on 8/10/10 by norfolkluego]
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mangogrooveworkshop
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| posted on 8/10/10 at 07:51 PM |
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Headon into a 4x4 and and the damage was everything hanging off the chassis.
bodywork, cooling system the electrical and the bones took the brunt of the impact.
chassis is straight and still good.
if you want super safety buy a volvo and wrap your self in a half ton of cotton wool.
Have been in a number of crashes in a 7 and we have come out ok.
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johnH20
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| posted on 8/10/10 at 08:08 PM |
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Might be worth looking at the detail design of some current space frame racing cars - FF and some of the sports car formulae mandate space frames and
also have to incorporate front crash boxes in some cases. I would guess that the special vulnerability of locost type cars is side impact so
particular attention in this area would be beneficial. Probably would not look like a locost any more though!
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interestedparty
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| posted on 8/10/10 at 08:17 PM |
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There's something about it in the IVA manual IIRC, about avoiding triangulation in the fron box area (if there is one) so as to allow more
progresive deformation
As some day it may happen that a victim must be found,
I've got a little list-- I've got a little list
Of society offenders who might well be underground,
And who never would be missed-- who never would be missed!
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iank
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| posted on 8/10/10 at 09:13 PM |
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The obligatory Caterham crash video. Safe enough for you*?
http://www.youtube.com/watch?v=svzmp56YPY0
A full cage does an awful lot more for chassis strength and accident survival than just keeping the tarmac off your helmet. It helps a lot for front
and side impacts as well.
*The driver broke his arm, since then I believe they've introduced arm restraints to prevent your arm coming out of the safety cell.
I'd avoid trying to build in deformable structures personally as there's a lot more to it than leaving a few diagonals out if you want to
ensure it doesn't make things worse in some accident conditions. iirc nib1980 used to design them for tintops.
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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tug
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| posted on 9/10/10 at 12:54 AM |
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Seems that a ladder chassis is pretty strong, I knew that. I was just wondering if any of you take that into a factor when building the chassis, guess
not
As we are on the subject of safety, if I use a steering column that came with an airbag. Should I remove it?
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MikeR
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| posted on 9/10/10 at 07:39 AM |
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depends do you like having an explosive device pointing at you that may go off any time? a device you're unable to test or design into the
car?
Friend used to design air bags for a living and they do a lot of analysis over them, its not like bolting on an escort rack to a sierra wheel.
personally, i'd remove it.
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iank
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| posted on 9/10/10 at 08:23 AM |
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You can't pass IVA with an airbag, but if you have a harness then an airbag isn't going to do anything useful.
p.s. Caterham is a spaceframe not a ladder. While a ladder chassis can be stiff (at the cost of some weight) side protection is minimal to say the
least.
If you're worried about side intrusion then you could fit buggy style nerf bars
 
Description
--
Never argue with an idiot. They drag you down to their level, then beat you with experience.
Anonymous
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l0rd
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| posted on 11/10/10 at 08:40 PM |
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does anyone remember that westfield that was chopped in half about a year and a bit ago?
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Ivan
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| posted on 12/10/10 at 07:16 AM |
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quote:
Originally posted by l0rd
does anyone remember that westfield that was chopped in half about a year and a bit ago?
Any car - no matter how well designed will suffer major damage hitting a strong enough pole or tree.
If not cut in half it will wrap right around it, to my mind a worse option as the passengers will wrap right along with the car - at least if it is
cut in half there is a chance that if you are not in the cut line you might survive. 
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scudderfish
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| posted on 12/10/10 at 07:55 AM |
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quote:
Originally posted by Ivan
quote:
Originally posted by l0rd
does anyone remember that westfield that was chopped in half about a year and a bit ago?
Any car - no matter how well designed will suffer major damage hitting a strong enough pole or tree.
If not cut in half it will wrap right around it, to my mind a worse option as the passengers will wrap right along with the car - at least if it is
cut in half there is a chance that if you are not in the cut line you might survive.
A few years back I saw some photos of a Lotus Exige that had flipped and landed on a concete post on the centre of the roll bar. Said roll bar folded
as if it were made of plastic (which it wasn't) as all the force of the crash was located on one point.
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coyoteboy
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| posted on 12/10/10 at 02:23 PM |
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you certainly can't design for every eventuality, all you can really do is cover the main likely events. The main problem is the nut behind the
wheel, but after that my main concern is frontal impacts, not side. I think it's pretty rare that you get T-boned unless you're a bad
driver yourself by pulling out on someone (who may be speeding, granted) so I eliminate that risk by ensuring I've good visibility and
accelerating swiftly. I have, however, had two non-fault frontal impacts that I could do nothing about, both of which were not pleasant experiences
despite being tin-top to tin-top impacts, with the majority of the damage being lasting spinal damage despite only travelling at 30mph - a closing
speed of 60mph hurts. Both of these could have been lessened if I'd assumed the other driver was a moron and was going to pull out when
I'm 10 yards away. I aim to reduce that risk by using my lights more often, really closely watching the driver's intentions and ensuring
the car will dissipate SOME energy, the problem with a low kit is it's more likely to go under a normal car (especially 4x4) and decapitate you.
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norfolkluego
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| posted on 16/10/10 at 06:21 PM |
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Had a good look around my car today, main damage is to the chassis rail where the rear lower wishbone mounts
 
D2
Twisted right around
Looks even worse from above
 
D1a
Twisted the whole centre section of the rail
 
D3
Makes the wheel look very squiffy
 
D4
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norfolkluego
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| posted on 16/10/10 at 06:24 PM |
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Rear wishbones actually look OK which is more than can be said for the front
 
D5
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