SAE Baja: Concept Generation & Selection Suspension and - - PowerPoint PPT Presentation

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SAE Baja: Concept Generation & Selection Suspension and - - PowerPoint PPT Presentation

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SAE Baja: Concept Generation & Selection Suspension and Steering Benjamin Bastidos, Victor Cabilan, Jeramie Goodwin, William Mitchell, Eli Wexler Wednesday, October 30, 2013 Overview Introduction Suspension Concept Designs o

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SAE Baja: Concept Generation & Selection

Suspension and Steering

Benjamin Bastidos, Victor Cabilan, Jeramie Goodwin, William Mitchell, Eli Wexler Wednesday, October 30, 2013

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Overview

  • Introduction
  • Suspension Concept Designs
  • Decision Matrix
  • Final Design
  • Steering Concept Designs
  • Decision Matrix
  • Final Design
  • Conclusion
  • References

Jeramie Goodwin 1

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Introduction

Client: Dr. John Tester

  • Problem Statement:

Design and build a safe, maneuverable, and versatile vehicle for competition use.

  • Goal:

Design a suspension and steering system that will meet the demands of off road racing.

Jeramie Goodwin 2

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Suspension Concepts

  • 4 Designs truly considered

○ Dual A-arms (front and rear) ○ Twin I-beam (front) ○ Semi-trailing arms (rear) ○ Solid Axle (rear)

  • Design that did not make it past preliminary choosing process

○ Twin Trailing Arm (front)

Jeramie Goodwin 3

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Suspension Design 1 (Front & Rear)

  • Independent Suspension
  • Advantages
  • Lightest weight
  • Alignment control throughout

travel

  • Disadvantages
  • Easier to break

(mostly due to CV axles)

Source: CarBibles William Mitchell 4

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Suspension Design 2 (Front)

  • Equal I Beams
  • Advantages
  • Allows for maximum travel
  • Best articulation
  • Disadvantage
  • Susceptible to bumpsteer
  • Radical camber change
  • Uneven tire wear due to

camber wear

Source: HM Racing Design William Mitchell 5

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Suspension Design 3 (Rear)

  • Trailing Arm
  • Advantages
  • Lots of travel
  • Truly independent
  • Strong
  • Simple
  • Disadvantages
  • Camber is static
  • Handling suffers at limit

Source: SAEBaja.net William Mitchell 6

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Suspension Design 4 (Rear)

  • Live Axle/Solid Rear Axle
  • Advantages
  • Tough
  • Simple design
  • Good articulation
  • Reliable
  • Disadvantage
  • Large unsprung weight
  • Wheels are not independent

Source: Motor Trend Eli Wexler 7

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Decision Matrix (Suspension Front)

Requirements A Arm Equal I Beam Solid Axle Simplicity (0.20) 4 4 5 Reliability (0.30) 4 4 5 Weight (0.30) 3 2 1 Cost (0.20) 4 3 2 Totals 3.7 3.2 3.2

Table 1: Suspension Decision Matrix (Front)

Eli Wexler 8

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Decision Matrix (Suspension Rear)

Requirements A Arm Solid Axle Trailing Arms Simplicity (0.20) 3 4 4 Reliability (0.30) 3 5 3 Weight (0.30) 4 1 4 Cost (0.20) 4 2 4 Totals 3.5 3.3 3.7

Table 2: Suspension Decision Matrix (Rear)

Eli Wexler 9

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Final Design (Suspension)

Eli Wexler 10

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Steering Concepts

  • 3 Designs considered
  • Pitman arms
  • Rack & pinion
  • Steer-by-Wire

Benjamin Bastidos 11

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Steering Design 1

  • Pitman Arm Steering Assembly
  • Advantages
  • Easily repaired
  • Robust
  • Strictly Mechanical Components
  • Disadvantage
  • “Dead Spot”
  • Response time

Benjamin Bastidos 12

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Steering Design 1

  • Pitman Arm Steering

Source: CarBibles Benjamin Bastidos 13

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Steering Design 2

  • Rack and Pinion
  • Types
  • Helical
  • Spur
  • Advantages
  • Smooth gear Meshing(Helical)
  • Simple mechanical design
  • Disadvantage
  • Steering Column Thrust Load(Helical)

Victor Cabilan 14

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Steering Design 2

Source: CarBibles Victor Cabilan 15

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Steering Design 3

  • Steer by wire
  • Advantages
  • Lightweight
  • Advanced Electronic Traction and Stability control
  • Disadvantage
  • Precise programing
  • Needs watertight connections
  • Needs to be well grounded

Victor Cabilan 16

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Steering Design 3

Source: Cvel Clemson Victor Cabilan 17

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Decision Matrix (Steering)

Requirements Rack & Pinion Pitman Arm Steer by Wire Simplicity (0.20) 5 4 2 Reliability (0.30) 4 5 2 Weight (0.30) 4 3 3 Cost (0.20) 4 3 1 Totals 4.2 3.8 2.1

Victor Cabilan 18

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Final Design (Steering)

Source: Car Bibles Victor Cabilan 19

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Conclusion

  • Front and Rear Suspension Concepts
  • Double A-arm (independent)
  • Solid Axle
  • I-Beam
  • Trailing Arm
  • Steering Design Concepts
  • Rack & Pinion
  • Pitman Arm
  • Steer-by-wire
  • Final Suspension and Steering Concepts
  • Trailing Arm/A-arm
  • Rack & Pinion

Jeramie Goodwin 20

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SLIDE 22

References

  • 1. http://www.carbibles.com/steering_bible.html
  • 2. http://www.autoblog.com/2009/06/22/report-s197-ford-mustang-could-have-

had-independent-rear-suspen/

  • 3. http://www.cvel.clemson.edu/auto/AuE835_Projects_2009/pillai_project.html
  • 4. http://www.hmracingdesign.com/html/suspension_kit_ranger_ibeam_hnm.html
  • 5. http://www.altairhyperworks.com/(S(3fu2zyrlbyi03xcofiue25jd))/hwhelp/Altair/hw

11.0/help/engsol/engsol.htm?rear_trailing_arm_suspension_system_svdd.htm

  • 6. http://forums.bajasae.net/forum/trailing-arm-suspension_topic753.html