ABSTRACT
The natural frequency of a flat isotropic plate clamped at the edges may have several modes of Vibration in which the plate exhibits a number of nodal circles and nodal diameters. For a corrugated diaphragm, because of its anisotropy, the nodal diameters are virtually unapparent except at extremely high frequencies. However, since the designer is usually interested in the lowest mode of Vibration, the fundamental equations derived herewith will be found useful for most applications. They are valid for an undamped, single-degree System within the linear range of the diaphragm. In deriving the equation for a diaphragm withrigid center, it is important to take into account the increase in the effective area of the diaphragm as well as the increase in the mass of the rigid center. The total mass of static condition is equal to the weight of the diaphragm plus the weight of the rigid center.
