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Aidan Lehal

Aidan Lehal

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Things to consider:

Contents:

Table of Contents
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Constraints and Requirements Considered

  • Roll Cage

  • Impact Force/Strength

  • Attachment requirements

  • Stiffness

  • Tube-Tube Attachment Type

  • Manufacturing Type

  • Price

Tube Profiles Considered

  • Square

  • Cylinder

  • Rectangle (volumetrically inefficient)

  • I-Beam (unidirectional applications)

Tube Types Considered

  • Hollow

  • Solid (too heavy)

Analysis of Tubes

After reducing the feasible tubes to 2 options (hollow round tube, and hollow square tube)

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, some research and simulations were conducted to assess the properties of each option. The dimensions of each tube were kept the same to for comparison purposes: 10in long tubes, 1x1x1/16in square, and 1x1/16in round.

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Decision Making Table

Steel Tube Analysis

Square (10 in of 1x1x1/16in)

Round (10 in of 1in D x 1/16in t)

Benefits

  • Probably easier to mount things onto flat surfaces (brackets, fasteners, subsystem aerobody panels, seats/belts, dynamics integration, etc.)

  • Moment of inertia (x/y) = 0.0345 (square) vs. 0.0203 (round)4

    • ~52% Stiffer as a beam (vertical/horizontal deflection)

      • for equivalent diameter

    • ~29% Stiffer in torsion

      • for equivalent diameter

  • Easier to clamp for welding or cutting3

  • Moment of inertia = 0.0203

    • ~27% lighter (~27% less volume of metal)

      • for equivalent diameter1

  • Complex curvature is easier to manufacture (roll cage)2

  • Better disperses the stresses, no real weak points from corners, consistent strength. This quality makes it easier to design with due to no orientation limits.

  • Cheaper/ft.

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  1. When designing to optimize strength to weight ratio, making a tube diameter larger before making it thicker will have a higher strength increase and lower weight increase than making it thicker. Observation from site: Tube Size vs Strength | Rorty

  2. Tubing formability can be used to our advantage when designing the chassis. In areas where multiple, smaller square tubes would need to be welded together, a round tube could accomplish the curvature required in one constant bend.

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MSXVII Chassis Design Page:https://uwmidsun.atlassian.net/l/c/zfCy6M90

Recommendation for MSXV

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Ideally a hybrid of both tubes could be used to maximize the benefits of both types. If a compromise of both cannot be made and it’s one or the other, asses assess the benefits of both based on the team’s goals/priorities, and the closest tube to achieving our goals should be picked (e.g. lightest = round, easiest to integrate with other subsystems = square).