Consider a round corrugated plate which is made by flax$/$epoxy composite with following mechanical properties:

$E_1=35$GPa,$E_2=9\mathrm{.}3$GPa,$G_{12}=4\mathrm{.}8$GPa,$v_{12}=0\mathrm{.}31$

The plate is constituted of $2$ layers with $(\frac{0}{90})$ lay$-$up$.$ Each layer thickness is $1$ mm $.$

The geometry parameters of the corrugation are:

$L=0,R=2cm.$

Find the stiffness matrices of the corresponding equivalent plate.