Guide To 2022 FSAE Frame Rule Changes
Keep these resources open during your team’s entire frame design process:
2022 FSAE Rulebook
2022 FSAE Structural Equivalency Spreadsheet (SES)
2021 FSAE Tech Inspection sheet
2022 suspension subteam geometry and loads
2022 ergo subteam packaging
2022 drivetrain subteam packaging
2022 will be the first year where we try to do early reviews on FSAE Michigan SES documents.
We plan on a long submission window.
IF your team has a finished design AND an SES document that is ready for review,
THEN we encourage you to upload long before 23:59:59.999 EST on the deadline.
There are other rule changes not mentioned here.
Just frame and SES topics are covered.
And I have skipped over everything that is simply a clarification of existing 2021 policies.
Miscellaneous
T.1.4.2 Driver Control Height
All driver controls must now remain below the top height of the Front Hoop.
Remaining inside the width of the Side Impact Structure, as always.
A few shifters were getting a little too high.
F.3.5.3.b-c Standard 6061-T6 Values
Teams using Aluminum 6061-T6 for SES equivalence are now required to use standard values for the T6 and welded condition.
There were too many problems with regards to realistic values or credible sources.
In addition to billet mounts, a smart team might find a weight advantage vs. standard steel tubes.
F.8 Front CHASSIS Protection
F.8.4.1 Standard Honeycomb IA
We are introducing a standard honeycomb Impact Attenuator (IA) in addition to the standard foam IA.
The specification is posted on fsaeonline.com under Series Resources, Technical Inspection Resources.
Using the standard honeycomb IA requires a Size C Front Bulkhead diagonal to avoid testing.
Considering a new test is required every year, we really want you to take this option.
Monocoque teams: Minimize front access holes, meet SES FB diagonal equivalence, and you also do not have to test the IA.
By our count, 85% to 95% of teams using honeycomb attenuators used the same specification in 2021.
F.8.7.5 Yearly Test For Custom IA
IA test data is valid for only one competition year.
Two issues prompted this:
Too many teams are not matching their test to the actual chassis and IA installation.
Material age at the time of manufacture and student fabrication ability can give very different results even if the same Composite IA design is constructed two years in a row.
F.8.5.7 IA Height
Top front edge of any IA needs to be at least 240mm window above lowest point of chassis as the SIS.
EDIT - 26 Aug Bottom front edge of any IA needs to be 220mm or less above lowest point of chassis at the SIS.
EDIT - 21 Dec Even if the SES throws a rejection, we will never fail a standard foam attenuator for being too low.
The only way a standard foam attenuator can fail the height requirement is by being too high.
SIS, IA, and HV protection are all getting lined up.
F.5.5 Reduce Bond Equivalence 50%
Applies everywhere on the car, but most teams will encounter this new bonding rule during IA attachment.
A 50% reduction is applied to all nominal and tested adhesive values.
This guarantees a safety factor >= 2.
Whenever using adhesives, develop the habit of large continuous bond areas that are unquestionably stronger than the components being bonded.
F.8.6.6 Front Wing Detachment
This has always been the rule and policy, but bears repeating:
Once broken off in a front impact, the front wing and wing mounts need to be able to move behind the AIP without hitting the chassis.
Suspension interference is ignored.
But wing mounts cannot be in front of the AIP.
Keep wings and mounts to the side or below the AIP.
F.8.7.7.a Dynamic Test For Composite IA
Due to very different failure mechanisms and forces between low and high strain rates, only Dynamic testing of Composite IAs will be accepted.
Quasi static: composites often peel back.
Dynamic impact: they shatter into dust.
F.8.3.2 120kN For Composite AIP
Composite Anti-Intrusion Plates (AIP) behind the IA must be able to carry 120kN.
Option a: No 3-point test required, but physically test a replica front bulkhead and composite AIP to 120kN.
Option b: 3-point test the composite sandwich, and meet 120kN equivalence in the SES.
Previously, a dynamic test for a Composite AIP behind the IA was allowed.
However, most IAs test in the 60kN range, meaning teams could be under the 120kN requirement by a factor of 2.
COVID-19 pushing 2020 cars into 2021 delayed the closing of that loophole.
TUBE STRUCTURES
F.5.10 Head Restraint Protection
The Head Restraint, including all supporting structure, cannot be the first thing to hit the ground in a rollover.
An extra hoop may optionally be added to increase the space available for the Head Restraint.
The Head Restraint cannot be mounted to this optional hoop; that creates the possibility of a direct load path into the Head Restraint in a rollover.
With forward Main Hoop Brace (MHB) tubes, there are three options:
Non-structural tubing or non-equivalent monocoque behind the Main Hoop (MH), with the Helmet and Head Restraint both completely ahead of the rear plane of the MH.
Triangulated structural tubing or mono equivalent behind the MH, with the Helmet completely ahead of the MH and the Head restraint completely within the rear envelope.
Optional hoop behind the MH, with the Helmet completely ahead of the MH and the Head restraint completely within and not connected to extra hoop.
With rearward MHB tubes:
Again, the helmet requirements do not change, and must be 50mm forward of the MH to MHB plane
The envelope for the head restraint goes MH to rearmost triangulated structure, even if that’s rearward of the MHB base
Extra envelope for the Head Restraint can be created with an optional hoop.
This does not help with Percy, but can help if you forget about the Head Restraint.
Don’t forget about the Head Restraint.
2022 SES Mount Bending
The 2022 SES will be posted on fsaeonline.com soon.
COVID-19 pushing 2020 cars into 2021 delayed the fix of an SES calculation error.
We really want bolted AIPs to use welded inserts through the Front Bulkhead tubes.
A welded insert through a Size B tube easily and automatically meets 15kN pullout and tearout requirements.
The calculation has always been intended to force tab designs to include gussets.
Fixing the calculation error will make it even more difficult for single, unbraced flanges to pass.
F.5.7.6 Front Hoop Side Angle
Below the Upper Side Impact, there is no restriction on the angle of the Front Hoop.
This gives flexibility to integrate suspension pickups, required Front Bulkhead Support (FBHS) tubes, and required Side Impact Structure (SIS) tubes.
The goal is to eliminate the sharp turns in some FBHS to SIS paths.
Mono teams, you also need to stop putting sharp turns into regulated structures.
Throughout 2022, we will analyze how to further regulate load paths.
Including considering future bans on V- or X- hoop braces, or single tube leg protection.
MONOCOQUE STRUCTURES
2022 SES 3-Point Tube Ovalization
The 2022 SES will be posted on fsaeonline.com soon.
The SES steel tube test will add a factor for tube ovalization.
Our analysis indicates a rig stiffness reported as ~80% or more in prior years should not apply a correction factor.
This will lower the calculated modulus of composite panels by at least 20% for the same layup tested for the 2022 season.
Test rigs with poor stiffness will see an even larger drop in corrected modulus.
F.7.10 Harness Loads And Testing
Based on FIA, belt manufacturer, and NASCAR data, test loads are increased to 15kN for each Shoulder Harness, Lap, and Anti-Sub attachment.
All loads must be applied normal to the panel, as a worst-case.
Shoulder Harnesses attached to a composite panel must test both attachments simultaneously, to a combined load of 30kN. Too many tests showed a mount easily carrying the old 13kN load while the panel itself was nearing bending failure, nowhere near good enough to carry both shoulder harness loads.
If combined (<125mm separation), a Lap and Anti-Sub attachment must be tested to 30kN. This is a big jump from the old 19.5kN combined.
EDIT - 10 DEC The span of the monocoque SH may be tested with a 30kN load split into two 15kN loads, or as a single 30kN load.
The unsupported span should replicate the chassis between the vertical SIS as shown below
The chassis-side harness attachment must be tested to 15kN.
A stronger hook may replace the harness attachment for testing the panel to 30kN.
Half-Monocoque With Rear Spaceframe
We expect the Main Hoop to be directly rearward, in line with the monocoque panels.
We expect the Main Hoop Mounts to be attached on both sides of the tube and slide over the panels.
F.7.6.2-3 SIS 3-Tube Equivalence
The SIS vertical panel may be equivalent to 2 or more steel tubes, with the floor equivalent to the remainder, if any.
F.7.5.2, F.7.7.2 Roll Hoop Bends Require Mounts
Below the top of the monocoque, F.7.9 attachments are required within 25mm of all FH and MH bends.
All bends, front and side view.
Fully laminated Front Hoops automatically meet this rule.
A single bend at the top of the FH is exempt.
All MH side-view bends above the monocoque still require triangulation to the MHB mount per F.5.8.3.b.
F.4.1.4, F.4.3.1 New Mono, New Panel Tests
Approximations of material age, test panel construction dates, and monocoque construction dates are required.
Test results must not be re-used for different monocoques in different years.
The intent is for the test panel to use the same material batch, material age, material storage, and student layup quality as the monocoque.
EV Accumulators
F.11.2.2.b High Voltage (HV) Protection
All side and rear HV protection top tubes need to be at least 240mm above lowest point in chassis.
F.10.5.7.e Max 2 Attachments Per Tube
The formerly popular and low-quality method of putting 5X 15kN mounts on a single bottom tube is no longer legal.
Many rules-legal tubes of a reasonable length would struggle to carry even one 15kN mount bending load in the middle.
At the very least, some load based attachments will need additional triangulation.
Good engineering practice would also reduce bending by pushing the mounts closer to the nodes.
2022 SES Mount Bending
The 2022 SES will be posted on fsaeonline.com soon.
COVID-19 pushing 2020 cars into 2021 delayed the fix of an SES calculation error.
The bending calculation is being completely reworked.
Single, ungusseted flanges will have a much more difficult time passing.
Well braced or blocky mounts should be relatively unaffected.
A welded insert through a Size B tube easily and automatically meets 15kN pullout and tearout requirements.
F.10.4 Holes
Rather than a 75% minimum height of interior walls, each accumulator segment must have at least 75% coverage on every side as well as between segments.
Holes should be no larger than 10mm diameter, and slots are prohibited.
No holes with line of sight to the driver are permitted, and the firewall does not count for this rule.
The container itself must be solid between the segments and the driver.
Once the lid is on, we expect each segment to be in its own room.
Use 10mm holes to reduce each face by up to 25%.
For the time being, sensible notches for connections between segments, connections outside the accumulator, or coolant tubes will not count towards the 25% limit.
But no more fan-size holes for fans.
The walls between the cells and the driver may not have any holes.
It is perfectly acceptable to expand each room around a segment for more airflow or electronics.
It is perfectly acceptable to add more rooms for those purposes.
Maintain 75% wall area around any additional rooms for a strong connection between all external walls, floors, and lids.
F.10.3.1.d, F.10.3.3 Multi-Layer
Making a full-width or length room for electronics over a layer of segments requires a horizontal wall fastened to each external wall section.
Placing one layer of segments over another layer of segments is not recommended. This requires each layer of segments to have a load path to chassis attachments, without passing through another layer of segments.
Attachments for every layer of segments must be well distributed front/rear, left/right.
F.10.2.3 Wall Fasteners
Welded, fastened, or bonded accumulator containers must show equivalence to the baseline weld.
Critical fasteners are no longer required for container walls.
EDIT 18 Aug - T.1.6.3.b Thermal Protection
Accumulators must maintain a 25mm air gap to the driver’s seat.
