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Member Types & Implementation

Member Types & Implementation

Apr 25, 2021

Aluminum Members

General aluminum properties and notes can be found on this Arm page.

Tubes

Aluminum tubes, as seen from some other successful URC teams, are most commonly assembled together/connected through welding. Fasteners however are also commonly utilized in some places, for example in attaching the linkages to the wheel hub in Monash's rover.

Examples:

Box-Tubes

Aluminum box-tubes, as seen in use by some other URC teams below, commonly use gussets and fasteners for assembling linkages together. Welding is less common although does make appearances.

Custom Linkages

Examples:

Carbon Fiber Members

General carbon fiber properties and notes can be found on this Arm page and this CF Research page.

Tubes

Round CF tubes used by other URC teams tend to be assembled using an array of options, including being directly fastened with holes, clamped into hubs, or assembled with aluminum tube fittings.

Examples:

Box-Tubes

CF box tubes when used by other URC teams seem to primarily make use of aluminum gussets and fasteners, in addition to aluminum tube fittings in some places.

Examples:

Comparisons

Member Style Comparison

Style

Pros

Cons

Style

Pros

Cons

Round

  • Higher strength to weight ratio compared to square tubes

  • More resistant to flexing and torsional twisting

  • More difficult to mount to compared to square tubes

    • More complex mounting solutions might result in more weight & space

Square

  • Easier to mount to compared to round tubes

    • less complex mounting results in less weight and less wasted space

  • Better for bending

  • Lower strength to weight ratio compared to round tubes

  • Less resistant to twisting and flexing

Custom

  • Save on weight by only reinforcing in required spots

  • More difficult / requires more effort to make custom carbon fiber parts

Member Material Comparison

Material

Pros

Cons

Material

Pros

Cons

Aluminum

  • Easier to make custom parts

  • Easier for mounting

  • Less expensive

  • Weighs more than CF

  • Not as strong as CF

Carbon Fiber

  • Weighs less than aluminum

  • Stronger and stiffer than aluminum

  • lower thermal expansion (not really relevant to us though)

  • Machining holes weakens CF

  • More complex mounting solutions can potentially create more weight and take up more space

  • Fails more suddenly compared to aluminum

  • Anisotropic properties make analysis more difficult

  • More expensive