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Front Wing Mounting DR1

Keiji Imai

4/16/23

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Agenda

  • DRDR summary
  • Logistics
  • Architecture
  • Design
  • Analysis
  • System Integration
  • Appendix

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CoDR Summary

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Part Scope

  • Increase car performance
    • Support front wing which increases downforce
  • Attaches frame to front wing
    • Interfaces with frame tabs and front wing plates
  • Inputs: Forces applied by front wing, mounting locations
  • Outputs: Deflection under load
  • I need help with determining loads and doing hand calcs and FEA

DRDR

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Lessons learned from previous cars

DRDR

MY19

MY20

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Lessons learned from previous cars

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  • Needed to weld tabs while car is on the ground and spring stiffness is set to get the right ride height (MY20)
  • Difficult to remove front wing (MY18, MY20)
  • Dovetails are difficult to machine
  • Endplates are structural in MY20 design, increasing weight

DRDR

- Stefan

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Rules

TLDR:

  • No excessive front wing oscillations while car is moving
  • No sharp edges

DRDR

TLDR:

  • Don’t use space above +/- 75 mm from the wheel

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Lessons learned from previous cars

DRDR

Wasim’s CAD

Alex’s proposed design

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More rules

TLDR: Don’t let front wing touch the ground

DRDR

TLDR:

  • Don’t use space above +/- 75 mm from the wheel

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More rules

TLDR: Stay within shaded area

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DRDR

3/14/2023

TLDR: Stay within shaded area

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More rules

TLDR: Can’t mount in front of Anti Intrusion Plate

DRDR

TLDR: Less than 25 mm deflection under 200N

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More rules

TLDR: Front wing cannot cause deceleration faster than allowed

DRDR

TLDR: Need to test or calculate force required to crush front wing

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Design Requirements

  • Rules legal + pass SES
  • Mount to frame and front wing
  • Don’t interfere with nosecone
  • Under .75” maximum deflection at 300N
  • Geometry while turning and suspension maxed out
  • Yield strength 1.2 factor of safety
  • Machinable in-house (waterjet + haas)
  • Removable without taking off nosecone
  • Less than 0.2 kg
  • Fails at peak impact attenuator load

DRDR

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Load paths

  • Downforce + bumps ~= 300 N
  • Turning radius = 7.5 ft = 2.3 m
  • Max turning velocity = 40mph = 18 m/s

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Downforce Hand Calcs

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Spacefill CAD

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Big Decisions: already made

  • Mount to aluminum ribs embedded inside front wing
  • Four bolts to mount to front wing
  • Four bolts to mount to frame

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Big Decisions: TBD

  • Diagonal supports necessary?
    • Will front wing bend?
  • Beams vs gooseneck
  • Gooseneck mounting
    • Dovetails vs tabs

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Diagonal Supports

  • Only necessary if we are worried about front wing bending

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Beams vs Gooseneck

  • CF Beams are lighter
  • Mounting is tricker
  • Potential for active aero

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Dovetail vs Tabs

  • Dovetail requires more machining time
  • Dovetail makes removing front wing easier
  • Tabs can be made adjustable (multiple mounting holes)

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Big Risks

  • If front wing breaks, we can get disqualified

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Logistics (on schedule so far)

DRDR

23

3/14/2023

Week

March

April

May

1

​

Fix design and do hand calcs

Assemble on car

2

DRDR

DR1

​

3

Initial design and FBDs

Run FEA and improve design

​

4

CoDR

Machine parts

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New Stuff

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Architecture

  • Tapered dovetail design
  • No diagonal supports for now (low deflection in hand calcs)

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Design

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Wing Mounting

  • 10-32 Bolts
  • Increased mounting rib E/D
  • Spacers

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Frame Mounting

  • Adjustable mounting
  • Tapered Slot
  • Two 10-32 Helicoils
  • Perpendicular 10-32 Bolt for fastening

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Better Hand Calcs

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Turning Deflection

  • Turn radius 7.5 ft
  • Turn speed 40 mph
  • Centripetal Force: 465 N
  • 4.7” long 3” wide 0.25” thick beam
  • 3 mm deflection

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Downforce Factor of Safety

  • used mechanicalc
  • Half of downforce
  • Z position offset
  • Actual FoS is way higher because now we have 6 bolts

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Logistics

  • Need to waterjet plates
  • Need to weld tabs on car in a couple weeks
  • Tabs need to be on car before frame gets anodized
  • Use HASS to machine dovetails

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Important Analysis

  • Bolt shear has ridiculous FoS (>180)
  • At peak impact attenuator load the bolts shear
  • Low deflection at peak cornering
  • Future analysis: FEA

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Schedule

DRDR

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3/14/2023

Week

March

April

May

1

​

Fix design and do hand calcs

Assemble on car

2

DRDR

DR1 We are here

​

3

Initial design and FBDs

Run FEA and improve design

​

4

CoDR

Machine parts

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Big Risks

  • Machining on Hass might take more time than expected
  • Waterjet might be unavailable
  • Diagonal Supports (if necessary) might be hard

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System Integration

  • Front wing ETA?
  • Modified front wing mounting ribs in CAD
  • Tolerances with the slot in the front wing are tight

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Appendix

Throw in any supplementary material here.

MY20 Front Wing Mount FEA

Engineering Requirements

Design review templates

FSAE Rules

Aerodyne DR Slides

Aerodyne Meeting Notes

Current state of aero

Front wing + Diffuser Mounting Google Doc

DRDR

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3/14/2023