Trebuchet

1
Trebuchet

• Team Members
• Linda Hib, Charlene Obille, Hanh Phan, James
  Santos

University of the Pacific School of Engineering
and Computer Science December 4, 2003
Lab Thursday 4 - 6
2
Overview / Outline

• Research
• Operation Development
• Guideline Theory
• Optimization Safety
• Design
• Design Simulations
• Sketches
• Construction
• Building the trebuchet

• Competition
• Rank based on score not distance
• Report
• Design Logs
• Final Sketches

3
Problem Definition
4
Introduction

• Our objective was to build a trebuchet that would
  launch a one ounce hacky sack with certain
  constraints
• The overall grade is based on the performance,
  analysis, and the implementation of the design

5
Constraints

• Dimensions
• 2.5by 3 by 4
• Weight
• 10lbs, anything over is penalized
• Counterweight
• 12 pounds
• Sling Counterweight Anchor
• Non - Metal
• Trigger
• 10 from Trebuchet
• Must be safe
• Dowel
• Half-Inch minimum
• Hardwood

6
Objectives/Criteria

• Build a trebuchet
• Use java simulation
• Analyze results
• Graph data
• Modify
• Competition
• Time limit
• Pickup
• Setup
• Launching in optimal conditions

7
Approach
8
L1 vs. Distance
9
Angle vs. Time
10
Preliminary Ideas

• Longer sling length
• Shorter counterweight anchor
• Swing arm with varied settings
• Wide base design
• Metal braces for support
• Trapezoid shaped sides

11
Sketches
12
Refinement

• Trapezoid sides -gt Triangle Sides
• Shorter sling length
• Longer Anchor
• Added an angled nail for sling release
• Added ring to release sling for smooth release
• Added metal sling track

13
Analysis

• Energy Conservation
• Dowel rotation (friction)
• Length of counterweight anchor
• Friction of release mechanism
• Length of sling

14
Decision / Implementation
15
Results / Discussion

• Performance
• 43
• Negative 25 due to weight
• .7 Offset
• Weight
• 18 pounds
• Score
• -12.1

16
Suggested Improvements

• Create a design that isnt so wide.
• Use thinner cut wood.
• Multiple pre set release angles.
• Smoother dowel rotation.

17
Conclusion

• The main problem with the trebuchet was that it
  weighed a lot.
• The weight of the trebuchet lead to poor score
  results.
• Design revisions lead to a drastic change in
  final design

18
Special Thanks

• Tool and Workspace help
• Wat Dhamawararam Buddhist Temple
• The Engineering Workshop
• Instructors
• Professor Litton Golanbari
• Influence
• Poeun Hib
• Stores
• Home Depot