Hi, I have a rectangular membrane (material: laminated aluminum like food packaging). The membrane is clamped around perimeter. From one side I have uniform (gas) pressure. The membrane is constrained from another side with rigid plate and, hence, do not deflect. But I can measure force that membrane pushes on the rigid plate and convert the force into pressure that I assume to be equal to pressure from another side of the membrane. I need to convert this pressure into deflection of the membrane like if the membrane do not have the rigid plate from one side. At least in one point on the membrane surface (centre). The deflection is not small - it is several (many) thicknesses of the membrane. What equation should I use?