In practice, members that carry transverse loads such as end plates and closures of pressure vessels, pump diaphragms, telephone and loudspeaker diaphragms, thrust-bearing plates, piston heads, diffusers, clutches, springs made of assemblages of plates, turbine disks, manhole covers, and so on, are usually circular in shape. Most important applications deal within the scope of equations derived for circular plates. A number of circular-plate problems have stress distributions that are symmetrical about the center. In this chapter, mainly the bending of circular plates of constant thickness under symmetrical loading and various boundary conditions are considered.

First, basic relations in polar coordinates are introduced. This is followed by discussions on boundary conditions for circular plates, axisymmetrical bending, equations of equilibrium, uniformly loaded circular plates with simply supported and fixed edges, the effect of shear on plate deflection, stresses due to concentrated loads, variously loaded annular plates, design tables for annular plates, and deflection and stress by superposition and energy methods. There is also a brief discussion on plates of variable thickness and the situations involving asymmetrical loading. A short catalog of solutions is tabulated. In all cases, the basic relationships in polar coordinates are used.