Select a Material for a Drone Arm

Engineering Context

A small inspection drone needs a replacement arm. The material must be light, stiff enough, manufacturable, and affordable.

What You Will Practice

• Use material properties in a trade study
• Distinguish strength, stiffness, density, and toughness
• Apply weighted decision criteria
• Defend an engineering recommendation

What You Need

• Candidate material data sheets
• Decision matrix template
• Calculator or spreadsheet
• Engineering notebook

Instructions

1. Review the mission profile, arm dimensions, expected load, and available manufacturing processes.
2. Compare aluminum, PLA, ABS, nylon, and carbon-fiber composite using density, stiffness, strength, toughness, cost, and manufacturability.
3. Choose weighting factors that total 100%.
4. Normalize or score each material consistently.
5. Complete the weighted decision matrix.
6. Perform one simple mass comparison using equal part volume.
7. Identify one property not captured well by the numerical matrix.
8. Write a recommendation with one risk and one verification test.

Engineering Requirements

• Compare at least five candidate materials
• Use at least six criteria
• Explain all weighting choices
• Include one quantitative mass comparison
• Identify a verification test before flight use

Constraints & Safety

• Use provided or credible property data
• Do not treat all composites as identical
• Recommendation applies only to the stated mission and geometry
• No physical load testing beyond approved classroom limits

What You Submit

• Material-property comparison table
• Weighted decision matrix
• Mass calculation
• Recommendation memo
• Risk and test plan

Reflection Questions

1. Which criterion controlled the result?
2. How would a crash-resistance requirement change the choice?
3. Why might the lightest material not be best?
4. What data would you verify with a supplier?