4.2 Random and Textile micromechanics results

If you expand Random Lamina and collapse everything else (by clicking the \includegraphics[width=14pt]{./Images/expand.png} sign), you get something like this:
\includegraphics[]{./Images/Random.png}

Laminas reinforced with random fibers are isotropic in the plane of the lamina. This means that when a random lamina is stretched or sheared, the deformation (i.e., elongation and/or shear strain) are the same in all directions, just like it happens for an Aluminum plate.

Isotropic materials are described by only 2 moduli, but 3 are listed for convenience: E, G, and the Poisson’s ratio. One property is redundant, so it can be calculated from the other 2 by using the famous formula:

  $\displaystyle \label{famous formula} G=\frac{E}{2(1+\nu )}  $   (4.2)

Finally, the properties for a lamina reinforced with a textile (fabric) are shown in section 9.2.