Dunk,
I guess I was not clear enough. I will try again.
Here are some of the BAD parts of the "AF" section.
"AF1.4 Notice of Intent - Teams planning to build a vehicle to this alternative rule set...
... must notify the Rules Committee ... by the date specified...
... detailing your team’s finite element capability and showing you can meet all [ALL!!!] analytical requirements...
... must include the email addresses and phones numbers of the team members who can answer any questions ...
... include ... your analysis approach, what software you used, the element types, mesh quality ... boundary conditions [blah, blah]...
... The Rules Committee will ... try to respond with their approval/disapproval within 15 days...
... SRCFs must be submitted no later than the due date ... Penalties ... will be imposed...
... Good analysis practice must be used ... all assumptions ... are subject to approval...
... A Nastran analysis deck and supporting documentation must be submitted...
... Tubes with wall thickness less than 0.047 inches ... cannot be included...
... Holes in tubes ... need to be applied to a shell or solid model of the tube with the hole or cutout geometry modeled...
... Offsets between tubes at nodes need a detailed analysis..."
Clearly, this tells the Teams they must wade through massive amounts of BUREAUCRATIC RED-TAPE, starting day one!
~o0o~
Here is one of the GOOD parts of the "AF" section.
"ARTICLE 4: STRUCTURAL REQUIREMENTS
AF4.1 Main Roll Hoop, Bracing and Bracing Supports
AF4.1.1 Load Applied: Fx = 6.0 kN, Fy=5.0 kN, Fz=-9.0 kN
AF4.1.2 Application point: Top of Main Roll Hoop
AF4.1.3 Boundary Condition: Fixed displacement ... of the bottom nodes of [F&MRH]...
AF4.1.4 Max Allowable Deflection: 25mm
AF4.1.5 Failure must not occur anywhere in structure."
Brief, and to the point!
The above is then followed by these similar "functional" load-test requirements.
"AF4.2 Front Roll Hoop...
AF4.3 Side Impact...
AF4.4 Front Bulkhead...
AF4.5 Shoulder Harness Attachment...
AF4.6 Lap & Anti-Submarine Harness Attachment...
AF4.7 Front Bulkhead ... Off Axis..."
Note that some of these could be combined into one test, such as pushing rearward on Front Bulkhead (= 4.4) while restraining the car with the seat-belt mounts (= 4.5 + 4.6). Also, I would do an upward push test on the floor, as mentioned last post, and/or other variations...
So, if the above are taken to be "real-world test" requirements, then the Team is being told to build a car, bring it to comp, and then expect the car to be poked and proded in all the directions that are thought necessary to ensure the safety of the driver. There is NO RED TAPE!
~o0o~
But, most importantly, the above functional requirements apply regardless of whether the Team wants to build a steel-tube-spaceframe car, or a CF/Aluminium-sandwich-monocoque, or a bamboo-reinforced-concrete-canoe. Any construction material/method is fine, just as long as real-world tests prove it strong enough to protect the driver.
So, all these following sections can be deleted from the Rules (along with much pruning of other sections).
"T3.4 Baseline Tubing...
T3.5 Alternative Tubing ... Geometry...
T3.6 Alternative Steel Tubing [with attendant "H-tests"]...
T3.7 Aluminium Tubing...
T3.8 Composite Materials...
T3.9 SES and SCRF [= much red-tape]...
...
T3.24 SIS for Tubeframe...
T3.26 Composite Spaceframe...
T3.27 Monocoques General +++++ [with many equivalency calcs and tests...]..."
~o0o~
To summarize.
* The idea of allowable "keep-in" zones is good.
* Also good are the "cockpit/percy templates" (effectively, "keep-out" zones internal to the car).
* Also good are real-world load test requirements (to help ensure driver safety), the seeds of which are in the "AF" section.
So, keep the above parts in the Rules.
Then, most of the rest of pages 24 to 87 can be deleted. This will give a clearer Rule Book, which is also more conducive to "educating young engineers"!
Z
(PS1: Much better tubeframe designs would be possible without the currently overly restrictive/prescriptive "Baseline" Rules.
PS2: I agree "minimum wheelbase" could be tossed...)