NATURAL FREQUENCIES OF FLAT OR SINGLY-CURVED SANDWICH PANELS WITH CORES OF ZERO FLEXURAL STIFFNESS.

ESDU 72016 provides a method of calculating the natural frequencies of vibration of initially unstressed flat or curved rectangular panels of sandwich construction with identical face plates. The core is assumed to have zero flexural stiffness and to be isotropic, but a moderate degree of orthotropy can be taken into account. The data are particularly applicable to other sandwich panels having cores of negligible flexural stiffness. The estimation procedure is presented in a graphical form and a computer program that calculates natural frequencies, based on this procedure, is given in companion ESDU 72017.