Equation is given for the maximum stress and deflection for circular flat plates subject to concentrated or distributed loads (pressure) with the edge either clamped or supported. In practice, the edge conditions are usually uncertain and some compromise must be made. The equations are only valid if the deflection is small compared to the plate thickness.

Symbols used:
r = radius of circular plate, (m, in)
p = uniform pressure loading, (N/m², lbs/in²)
v = Poisson’s ratio (often assumed to be 0.3)
E = Young’s modulus, (N/m², lbs/in²)
t = plate thickness, (m, in)
s _m = maximum stress, (N/m², lbs/in²)
y_m = maximum deflection, (m, in)

Circular plate, uniform load, edges clamped equation and calculator.

Stress At Edge

Deflection at center

D = flexural rigidity= Et³/(12 ( 1 -v²)