Composites Short Course

This presentation covers the basics of classical laminated plate theory as applied to composites. It is based on a short course taught by Dr. Steve Griffin at Duke University. The material is courtesy of Dr. Griffin, and was converted from his original Powerpoint presentation.

A short introduction to laminated composites

Assumptions

3-d Orthotropric Assumption

2-d Assumption

Which constants do we specify and how do they relate to stiffness (or compliance)?

What about ply angle?

What’s a stacking sequence?

Usually, we want to know the combined response of laminate

We can define resultant forces and resultant moments

Using stress/strain relations, ply angle, thickness and strain assumption, we get the celebrated ABBD matrices

The formulae for ABBD are

Now we have everything we need to relate applied moments and forces to strains and curvatures

Look at some cases of E-glass/epoxy .125 plies

What if I want a composite to act like metal in-plane?

Quasi- or Pseudo- Isotropic Composites

What if I want a plate to bend when I pull it?

What if I want a really stiff plate in x-direction, that has to act like metal in-plane?

What about more complicated structures

How do I make a composite?

What happens during a cure?

What happens during a cure?

Room temperature cure composites