Re: Composites

Matt Oliverius wrote:
> 
> Hi all,
> I am trying to calculate composite moduli for a (45/45/45/45) laminate in 1
> degree increments from 0 to 360 degrees.  However, the equations I am
> finding in textbooks are undershooting the modulus.  For example suppose my
> fiber modulus (E) is around 20MSI and my matrix modulus (E) is 1 MSI.  Then
> when I plug theta of 45 into a transformation equation (assuming 0 is the L
> direction of the composite), then I come up with a modulus of 2MSI, when it
> should be around 20MSI.  Does anyone know what might be wrong?  Is there an
> assumption about the stackup in these equations that I might be missing?
> If so, where can I find references to the generalized solution E = f(theta)
> for any stackup?

The ply has a 20 msi modulus in the fiber direction.  What about across the 
fibers (90 deg)?  If that is 0, then the laminate modulus is dependent only 
on the matrix.  

- CJF.