Thank you, Peteroznewman!nMy goal is to get the same answer as the ANSYS simulation. The pressures are very small so both linear and nonlinear solution gives the same answer for maximum deflection. I actually tried turning on Large deformation and turning it off and they both give the same answer because the deflection is less than the thickness of the plate. My analytical calculation does not much the ANSYS solution. nIs ANSYS using a different equation or model when calculating circular plate than w = pa^4/64D?nThank you.n