Stresses in a welded diaphragm due to boundary contraction and normal uniform pressure

The boundary contraction of a small welded circular diaphragm is determined semi-experimentally by utilizing a theoretical relationship between boundary contraction, applied normal pressure and measured deflection. The relationship is nonlinear since large deflections have to be considered. Stresses are determined by a method that uses slope measurements on casts of the deflected diaphragm surface and the value of the boundary contraction as input. Radial and tangential membrane and bending stresses of a typical diaphragm are obtained as application example. The approach should particularly be useful in cases where boundary contraction cannot be measured directly because of design restrictions.