View Single Post
  #50  
Old 03-05-2010, 07:36 AM
deuce_454's Avatar
deuce_454 deuce_454 is offline
Senior Member
 
Join Date: May 2006
Location: Copenhagen, Denmark
Posts: 1,612
Thanks: 0
Thanked 1 Time in 1 Post
Default

Quote:
Originally Posted by legend View Post
very nice work

those frames look very strong in static bending, but would be poor torsionally. What do you guys do to stop it twisting?
WHAAAT??

I just saw this post and had to object... a 5x2.5 .125 wall box profile is anything but weak torsionally...

and since they are connected in both ends (in the front by the front crossmember) applying a torsional load on the car will be absorbed by both the rails ... as they will have to flex allong their longitudinal axis, doing that to a pair fo 5x2 box profiles is no small task.. its much

some quick numbers for the doubters out there:
5x2-1/2x1/8 square has a torsional stifness constant of 4,40 in4 and
1,9x0.145 round has a torsional stifness constant of 0.586 in4..
so you would need more than seven parallel round tubes on each side arranged like the ironworks truck with the tube chassis to be as stiff torsionally as the one box..

source: http://www.steeltubeinstitute.org/pd...n_brochure.pdf

and on another note... it is a tube frame :-) its just square tubing
__________________
Elwood:We're 105 miles from Chicago, we have a full tank of gas, half pack of cigarettes, it's dark out and we're wearing sunglasses.
Jake: Hit it.

Last edited by deuce_454; 03-05-2010 at 08:14 AM.
Reply With Quote