The document summarizes a panel project involving the design, optimization, manufacturing, and testing of stringer concepts for panels. It describes exploring a Z-stringer and witch hat stringer design. The team agreed on design parameters like a 90 degree web angle and adjusted the height at the expense of width for optimization. The final design is specified with dimensions. Testing showed discrepancies with the original dimensions likely due to coding errors, manufacturing tolerances, and plastering issues. Lessons learned included scheduling, measuring twice, alternative solutions, and checking work. The design was successful overall despite challenges.

1. Panel Project
Nick Moger
Bradley Michael
Robin Cox

2. Scope and Objectives
• Design
• Optimization
• Practice
• Manufacturing
• Testing

3. Scope and Objectives
www.tomsplanner.com

4. Stringer Concepts
• Z-Stringer
– Not strong enough
• Witch Hat Stringer
– Simple triangular shape

5. Failure Conditions
• Web bend angle
– Stress Cracks
• Area under hat
– Most exposed panel

6. Optimization
• Kept flanges constant
– Minimum 1.5x rivet diameter
• Agreed upon 90°web angle
– Easy to check
• Adjust height at expense of width
– Too high then too wide

7. Final Design
Flange end to Flange end = 2.3 inFlange end to Flange end = 2.3 in
Height = 0.64 inHeight = 0.64 inWeb Length = 0.9 inWeb Length = 0.9 in

8. Final Design
• Quantity - 5
• Rivet Spacing
– 23/32nds
in
– 18/32nds
in (from the top and bottom)
– Shop aid/jig for “perfect” rivets
• Stringer Spacing
– bs-s= 0.5 in
– bs-f = 5/32th
in

10. Predicted vs. Reality
• Original dimensions
-Fabrication not possible; stringers too wide
• Didn’t account for possible misalignments

11. Reasons For Discrepancy
• Coding
– Code was not perfect
• Manufacturing
– Stringers were not bent to exact measurements
• Plastering
– Our biggest problem!
Snap Crackle Pop
Failure Load (lbf) 18,301 19,635 17,731
Percentage Range
(%)
22.6 16.9 25.0

12. Lessons Learned
• Scheduling is important
• Measure twice, cut once
• Multiple ways to a solution
• Fear of the Unknown
• Daaaable Check! (Laugh if you get it)

13. Conclusion
Snap Crackle Pop
Percentage Range
(%)
16.8 10.7 19.4
• Design Successful!

14. Questions?