Head restraint mounting bar

[apoorv]

Hi guys,

We have designed our head restraint mounting bar such that it is a bended tube.

The rule T3.5.5 says that If a bent tube(or member consisting of multiple tubes that are not in a line) is used anywhere in the primary structure, other than the front and main roll hoops, an additional tube must be attached to support it. The attachment point must be the position along the tube where it deviates farthest from a straight line connecting both ends.The support tube must have the same diameter and thickness as the bent tube, terminate at a node of the chassis, and be angled no more than 45 degrees from the plane of the bent tube.

I have a doubt that does head restraint mounting bar comes in primary structure and needed to satisfy this rule (provide support member at 45 degree to a node at chassis). Also in T5.6.3 its not mentioned to provide a support to the mounting bar (only force of 890N is mentioned). Is this design okay?

Apoorv,
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[tromoly]

Who are you? What school do you attend? Which event are you planning to attend?

Submit a rules clarification, easiest way to get the correct answer.

[apoorv]

I am apoorv from SRM University, India. We will be going to formula student Italy 2015.

Apoorv,
chassis engineer.

[SomeOldGuy]

The head restraint will be fine but I believe the side pod boxes would be deemed illegal (maybe not illegal to the letter of the rule but...).

[DanielH]

Is your head restraint the tube coloured red or is it the small tube above that? Either one seems legal to me, but if the red tube is your shoulder harness bar, it's not legal.

Also, the primary structure is defined under T3.3g
"Primary Structure – The Primary Structure is comprised of the following Frame components:
i. Main Hoop,
ii. Front Hoop,
iii. Roll Hoop Braces and Supports,
iv. Side Impact Structure,
v. Front Bulkhead,
vi. Front Bulkhead Support System and
vii. All Frame Members, guides and supports that transfer load from the Driver’s Restraint System into items 1 through 6."

[apoorv]

@someoldguy why side pods would be illegal?
@DanielH yes the red bar is the head restraint mounting bar.

[Adam Farabaugh]

Your sidepods have zero triangulation to resist deflection in the up/down direction.