SAE MINI BAJA Front & Rear End Rear End: Jacob Ruiz Front - - PowerPoint PPT Presentation

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SAE MINI BAJA Front & Rear End Rear End: Jacob Ruiz Front - - PowerPoint PPT Presentation

Oct 31, 2022 191 likes •599 views

SAE MINI BAJA Front & Rear End Rear End: Jacob Ruiz Front End: Will Preston Lucas Cramer Jacob Grudynski Aaron King Jesse Summers Michael Edirmannasinghe Proudly Sponsored By: Project Description SAE Baja is a collegiate

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SAE MINI BAJA Front & Rear End

Front End: Will Preston Jacob Grudynski Jesse Summers Michael Edirmannasinghe

Proudly Sponsored By:

Rear End: Jacob Ruiz Lucas Cramer Aaron King

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SLIDE 2

SAE INTERNATIONAL

Project Description

  • SAE Baja is a collegiate competition in which teams design, build, and test off-

roading vehicles

  • Vehicles are presented in competition to a fictitious firm for possible

manufacturing

  • Designs must abide by Baja SAE competition rules in order to compete
  • Must be able to perform well in Dynamic and Static events
  • Sponsors include W.L. Gore, NAU and SAE International
  • Acceleration Test
  • Braking Test
  • Hillclimb
  • Endurance

Jesse Summers/10-8-19/SAE Baja/F1908

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Black Box Model - Rear End

Aaron King/10-8-19/SAE Baja/F1908

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Detailed Decomposition Model (Rear End)

Aaron King/10-8-19/SAE Baja/F1908

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Black Box Model - Front End

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Will Preston/10-8-19/SAE Baja/F1908

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Detailed Decomposition Model (Front End)

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Will Preston/10-8-19/SAE Baja/F1908

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Concept Generation – Rear End

Jacob Ruiz/10-8-19/SAE Baja/F1908

Advantages:

  • Increases travel
  • Lower unsprung weight
  • Better ride quality
  • Independent suspension

Disadvantages:

  • Long rear links
  • Hard to manufacture

Figure 1: Tailing Arm with Links Figure 2: Tailing Arm with Links from Rear

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SAE INTERNATIONAL

Concept Generation (Double Wishbone) - Rear End

Aaron King/10-8-19/SAE Baja/F1908

Advantages:

  • Allows movement
  • nly in vertical

direction to fix the toe Angle Disadvantages:

  • Requires a change

to the frame

  • Heavy

Figure 3: Double Wishbone

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SAE INTERNATIONAL

Lucas Cramer/10-8-19/SAE Baja/F1908

Advantages:

  • Lightweight
  • Easy Mounting
  • Durable

Disadvantages:

  • Any failure leads to full system failure
  • Difficult hub/axle connections

(manufacturing)

Concept Generation (Single Part Trailing Arm) - Rear End

Figure 4: Tailing Arm Single Part Figure 5: Tailing Arm Single Part Only

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SAE INTERNATIONAL

Decision Matrix – Rear End

Lucas Cramer/10-8-19/SAE Baja/F1908

Decision Matrix​ CN's Weight​ Double Wishbone​ Single Piece Trailing Arm​ Trailing Arm Two Lateral Links​ Score​(1-5) Weighted​ Score​(1-5) Weighted​ Score​(1-5) Weighted​ Safe​ 15% 5 0.75 2 0.3 4 0.6 Durable​ 15% 3 0.45 2 0.3 4 0.6 Lightweight​ 20% 1 0.2 5 1 3 0.6 Ease

  • f Production​

10% 2 0.2 3 0.3 3 0.3 Cost 15% 2 0.3 5 0.75 3 0.45 Performance 25% 4 1 3 0.75 5 1.25 Totals:​ 100% 2.9 3.4 3.8

Table 1: Decision Matrix (Rear End)

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SAE INTERNATIONAL

Concept Generation – MacPherson Strut

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Figure 6: MacPherson Strut model [1]

Jesse Summers/10-8-19/SAE Baja/F1908

Advantages:

  • fewer number of parts

Disadvantages:

  • not used for off-road platforms
  • not easily mounted to tube frames
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SAE INTERNATIONAL

Concept Generation - Double Wishbone A

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Figure 7: Double Wishbone A Advantages:

  • Maintains desired alignment specifications

Disadvantages:

  • Limited space between components, restricts maneuverability
  • Difficult to repair

Will Preston /10-8-19/SAE Baja/F1908

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SAE INTERNATIONAL

Concept Generation – Double Wishbone B

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Figure 8: Double Wishbone B

Michael Edirmannasinghe/10-8-19/SAE Baja/F1908

Advantages:

  • Consistent alignment
  • Allows space for steering, drivetrain

components Disadvantages:

  • Requires high upper shock mounting

point

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Decision Matrix – Front End

Jesse Summers/10-8-19/SAE Baja/F1908

Table 2: Decision Matrix (Front End)

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CAD – Rear End

Jacob Ruiz/10-8-19/SAE Baja/F1908

Figure 8: Rear End Back View [2,3] Figure 9: Rear End Isometric View [2,3] Figure 10: Rear End without Tire [2,3]

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CAD – Front End

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  • Rack and Pinion Steering

System

  • Aluminum components.
  • Expecting Aluminum

Steering Column.

  • Track Width
  • FE – 55 in
  • RE – 58 in
  • Wheelbase – 60 in
  • Ackermann angles
  • L – 48.72 degrees
  • R – 28.28 degrees
  • Mounting angle
  • 24.62 degrees

Michael Edirmannasinghe/10-8-19/SAE Baja/F1908

Figure 11: Rack and Pinion Steering

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CAD – Front End

Jake Grudynski/10-8-19/SAE Baja/F1908

Figure 12: Front End CAD Isometric View Figure 13: Front End CAD Top View Figure 14: Front End CAD Hub

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CAD – Front End

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Jake Grudynski/10-8-19/SAE Baja/F1908

Figure 15: Front End CAD

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Bill of Materials – Rear End

Jacob Ruiz/10-8-19/SAE Baja/F1908

Ball Joint Rod Ends 5% Tube Mounting tabs 1% Mounting Tabs 2% Rear Hub 9% Trailing arm Tubing 10% Rear Links 3% Rear Shocks 49% Rod Ends 2% Rim 6% Tires 13%

Qty Description Cost Total Cost 8 Super-Swivel Ball Joint Rod Ends $ 21.94 $175.52 1 Steel Sheet $ 47.53 $47.53 1 Steel Bar Stock $ 57.94 $57.94 4 Polaris Rear Hub $ 75.99 $303.96 4 Steel Tubing $ 77.59 $310.36 2 Aluminum Rod $ 40.63 $81.26 1 Fox Factory Series Float 3 Evol RC2 $ 1,595.00 $1,595.00 8 1/2" Ball Joint Rod Ends $ 7.08 $56.64 2 Rim, Flat Black $ 92.80 $185.60 2 Rear Tire $ 205.99 $411.98 Total $3,225.79

Figure 16: Rear End Budget Breakdown Table 3: Rear End Bill of Materials [3,4,5,6]

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Bill of Materials – Front End

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Table 4: Front End Bill of Materials

Michael Edirmannasinghe/10-8-19/SAE Baja/F1908

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Questions?

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References

[1]P. Czop, "Application of an Inverse Data-Driven Model for Reconstructing Wheel Movement Signals", Research Gate, 2019. [Online]. Available: https://www.researchgate.net/figure/A-schematic-view-of-a-McPherson-front-strut-suspension- system_fig1_273249518. [Accessed: 07- Oct- 2019]. [2]B. Koubaa, "Grabcad," 10 May 2012. [Online]. Available: https://grabcad.com/library/bicycle-shocks-burner-rcp. [Accessed 7 October 2019]. [3]McMaster-Carr. [Online]. Available: https://www.mcmaster.com. [Accessed 6 October 2019]. [4]A. Marketplace, "Polaris New OEM Bearing Ball Sealed," [Online]. Available: https://www.amazon.com. [Accessed 6 October 2019]. [5]Fox, "FACTORY SERIES FLOAT 3 EVOL RC2," [Online]. Available: https://www.ridefox.com/product.php?m=atv&t=shocks&p=1149&ref=family. [Accessed 6 October 2019]. [6]Partzilla. [Online]. Available: https://www.partzilla.com/product/polaris/1520263- 463?ref=d5473e3fd0ef85e6063d67b2d931889e5ebdedca. [Accessed 6 October 2019]. [7] Dixon, Suspension geometry and computation, 1st ed. Chichester: John Wiley, 2009.

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SLIDE 23

SAE MINI BAJA FRAME & DRIVETRAIN

Frame: Jacob Kelley Riley Karg

Proudly Sponsored By:

Drivetrain: Tye Jorgenson Jacob Najmy Kaleb Brunmeier

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SAE INTERNATIONAL

Project Description

Tye Jorgenson Figure 1: 2018-19 NAU Baja [1] General:

  • Design and build a single-seat, all-terrain vehicle to compete in the SAE Baja Collegiate Competition
  • Entire vehicle built within the limits of the official rulebook
  • Performance measured by success in the static and dynamic events at competition in April

Frame:

  • Cage designed and fabricated to withstand critical failure during normal operation, collision, or roll over
  • Interfaces with all other sub-teams
  • All welding done in-house

Drivetrain:

  • Responsible for transmitting engine power to vehicle propulsion
  • Up to 150 bonus points for operational 4WD/AWD system
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SAE INTERNATIONAL

Tye Jorgenson

Frame and Drivetrain

Weight of Driver and Drivetrain Forces From Suspension Throttle Position Withstand Applied Forces Hold Component Positions Electrical Input Forward Acceleration Noise and Heat

Black Box Model

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Detailed Decomposition Model

Tye Jorgenson Weight of Driver and Drivetrain Forces From Suspension Electrical Input Convert Forces into Potential Elastic Energy Forces Elastic Energy Convert Potential Elastic Energy into Opposing Forces Withstand Applied Forces Hold Component Positions Throttle Position Forces Force Convert Mechanical Force into Chemical Energy Release Chemical Energy Convert Chemical Energy Release into Mechanical Energy Noise and Heat Losses Condition Mechanical Energy into Useful Form Mechanical Energy Forward Acceleration Mechanical Energy

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Drivetrain Concept Generation (ECVT)

Jacob Najmy Figure 2: Spring 2019 Linear Design [1] Generation Type: Gallery Method, Directed Search Advantages: ✓ Lower initial cost ✓ Robust Design Disadvantages: × Hard to Manufacture × Large Moment on Stepper Motor Bracket × Heavy Design with Solid Shafts Figure 3: Fall 2019 Design Iteration Generation Type: Gallery Method, C-sketch Advantages: ✓ User Input or automatic mode ✓ Different modes based on terrain ✓ Centralized Design (No moment on stepper motor) Disadvantages: × Battery reliant × Possible stepper motor overheating

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Drivetrain Concept Generation (Transfer Case)

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Figure 4: Concept 1 Generation Type: Gallery Method, Directed Search Advantages: ✓ Allows motion to be transmitted perpendicular to the engine ✓ Simple Gear geometry that allows for easy of manufacturing Disadvantages: × Larger Housing requiring more lubricant (Heavy Design) × Complex Machining × Does not allow for placement of CVT within the frame Figure 5: Bevel Gear Concept 2 Generation Type: Gallery Method, Directed Search Advantages: ✓ Allows motion to be transmitted perpendicular to the engine ✓ Disengaged front driveline for less driveline resistance Disadvantages: × Complex design × Complex machining × Geometry restriction (Mounting at an angle for the CVT) Jacob Najmy

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Drivetrain Concept Generation (Gear Reduction)

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Figure 6: Spur Gear Reduction [##] Advantages: ✓ Built-in transmission guard ✓ Environment Proof Disadvantages: × Heavy ‘Wet’ System needs lubricant × High Machining Cost and Schedule Critical × High Tolerance Gear Mating Figure 7: Pulley Gear Reduction Advantages: ✓ Efficient Power Transmission (98%) ✓ Lightweight ‘Dry’ System does not need lubricant ✓ Little drivetrain noise at high speeds Disadvantages: × Tensioning require × Maintenance intensive (belt replacements) Jacob Najmy Generation Type: Gallery Method, Directed Search Generation Type: Gallery Method, Directed Search

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Drivetrain Concept Selection: Pugh Charts

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Kaleb Brunmeier Figure 8:Speed Reducer Pugh Chart Figure 9: Transfer Case Pugh Chart

  • Criteria derived from House of Quality criteria
  • Speed Reducer Designs to Consider: Spur Gear Reduction, Timing Belt Reduction
  • Transfer Case Designs to Consider: Differential Concept 1, Simplified Bevel
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Drivetrain Concept Selection: Decision Matrices

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Kaleb Brunmeier Figure 10: Speed Reducer Decision Matrix Figure 11: Transfer Case Decision Matrix

  • Major Criteria: Weight, Efficiency, 2-Stage Reduction
  • Minor Criteria: Audible Volume, Approximate Height, Maintenance
  • Final Speed Reducer: Timing Belt Drive
  • Reduced Weight, Slight Volume Increase
  • Final Transfer Case: Simplified Bevel System
  • Least Weight, Highest Efficiency (least components)
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SAE INTERNATIONAL

Jacob Kelley

Straight Front Bracing Members

  • Higher top impact resistance

Bent Front Bracing Members

  • Allows wider cockpit area

Additional Bend in Roll Hoop

  • Distributes impact loading evenly

No Additional Bend in Roll Hoop

  • Bigger driver clearances

Strait Upper Nose Members

  • Higher front impact

resistance Bent Upper Nose Members

  • Narrows nose for front end

Figure 12: Read View Figure 13: Front View Figure 14: Top View

Frame Concept Generation

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Frame Decision Matrix

Riley Karg

  • Few factors are decided upon.
  • Most of frame geometry is predetermined.
  • Even material selection lacks diversity of options.

Figure 15: Frame Decision Matrix

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Frame Decision Making

Riley Karg

  • Must be compatible with front and rear suspension.
  • Must allow space for all other subsystems.
  • Must ensure certain subsystems are fully enclosed by the frame.
  • Must comply with all rules.
  • Must be able to easily adapt while in design phase.

Design Necessities Accounting for Design Necessities

  • Multiple meetings/briefing with other sub-teams.
  • Understanding how the frame affects other sub-teams.
  • Understanding how other sub-teams affects the frame.
  • Constant design updates being created and shared with the entire team.
  • Checking each change with the rules to ensure compliance.

Figure 16: Frame V2.0 Figure 17: Frame V1.1

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Frame Material Calculations

Riley Karg Figure 18: Frame Material Calculations

  • Used excel sheet to calculate various materials and sizes.
  • Objective is to find the lightest weight material that meets the minimum requirement.
  • For primary tubing, a 1.25" OD and 0.065" wall thickness yielded the lowest weight.
  • For secondary tubing, a 1.00" OD and 0.058" wall thickness was chosen.
  • For tertiary tubing, a 1.00" OD and 0.035" wall thickness was chosen.
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SAE INTERNATIONAL

Jacob Kelley

No Additional Bend in the Roll Hoop Adhering to rules on bent member lengths Easier to fabricate Bent Front Bracing Members Strong enough in FEA Larger cockpit Strait Upper Nose Members More compact nose Easier to fabricate Better interface for front end to work with Higher front impact resistance

Frame Final CAD

Figure 19: Rear View Figure 20: Top View

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Frame FEA

Jacob Kelley Nine Scenarios simulated for multiple impact conditions

  • Used overestimates for impacts

and weights

  • Lowest FOS of 1.65 was the top

front impact with driver

  • This is lower than we would like

but this scenario highly unlikely Figure 21: Frame FEA Analysis

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Bill of Materials

Tye Jorgenson Figure : Drivetrain/Frame BOM

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Questions?

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References

[1] (Najmy, Janshah, ElShamsi, Jorgenson, & Smith, 2019) Final Proposal for SAE Baja ECVT, 2019 [2] Grainger. Power Drive Pulleys. https://www.grainger.com/category/power-transmission/sheaves-and-pulleys/timing-belt-pulleys