Practicalities

Question 1

What are 5 rules of thumb for laminate design?

Answer 1

1. Simplify
2. Use a balance symmetric layup - prevents coupling between shear and bending loads (this isn’t as important for tubes)
3. Use same materials in all plies
4. Use either a +/-θ layup of a sequence of 0/45/90 plies
5. Have at least 10% off axis 45/90 degree plies to prevent splitting and high poissons ratio

Question 2

What are 3 manufacturing methods for composites?

Answer 2

Roll wrapping (like hand layup) - sequence of 0, 45, 90 plies for pre-preg layup 
Filament winding - +/- θ layup 
Pultrusion Predominantly aligned along axis but can have some 45 degree plies fed in

Question 3

What is autoclaving?

Answer 3

A consolidation method (remove air bubbles that weaken structure) for composites that uses a 6 bar pressure and vacuum inside bag, with high temperature.