Alternative Tubing (T 3.6.2)

[konpouh]

Hi Guys,

My name is Konstantinos and i am the frame engineer of Aristotle Racing Tram Electric (ARISTURTLE) Greece .I've gone through many post about tube wall thickness on the Forum but i couldn't find an answer about my problem.

My team has 30 OD and 2mm wall thickness for the roll hoops, 28X1.5 and 25X1.5 for all the other members of the frame, so practically we dont maintain the EI in the same cross-sectional area. The part that i couldnt understand is if all teams with alternative tubing have to construct a "H" test as mentioned in T3.6.2 and if so, can anyone explain how to manufacture it?

Any help would be appreciated.

Thank you in advance,

Konstantinos

[Adam Farabaugh]

What about T3.6 do you not understand?

First thing is first, for any alternate tubing while using the T.xxx drivers cell rules, the intent is that, for every regulated tube, your tube has equal or greater cross-sectional area and equal or greater EI (and since all tubing is treated as baseline steel, equal or greater I).

Obviously to do this you can increase OD and decrease wall thickness, and by thinking about this you can see some benefits. Now think about the limiting case. Would you build a car out of tubing 300mm diameter with .1mm walls? Welding thin-walled tubing becomes an issue, which is why there is a minimum wall thickness table for no-test welds, and another less conservative table for tested welds.

From the numbers you gave, you are in the no-test weld table for all tubes... but I have not done your area and bending inertia calculations, so make sure you've done those right (the SES will check your work when you fill it out).