Hi! I want to calculate the deflection of a circular membrane driven by a piezoelectic disk set on the top of the membrane. I found a relation between the deflection and the inverse bending radius K of the deflection but only for a rectangular beam: d2(deflection)/d2X where X is the length of the beam. Could anybody help me to find the relation for a membrane? I found deflection = (K/2)*(X2+ Y) by assuming that my membrane could be seen as the cross of two identical beams in X and Y directions. In this case we have d2(deflection)/d2X = 1/K and d2(deflection)/d2Y = 1/K I think it's too simplified and I am not sure my calculation is good anyway. Thank you for your advice.