ESDU 75030:1995

ESDU 75030 gives comprehensive curves that enable the natural frequencies to be calculated for the first few modes of vibration of plates having any combination (symmetric or otherwise) of edge conditions from free, simply-supported and clamped. The data apply to plates having the ratio (length of shorter side)/(thickness) greater than 10 and were computed for a Poisson's ratio of 0.3 although a method for taking into account the effect of other values is explained. Results obtained using the curves are accurate to within three per cent. The curves apply to initially unstressed plates but a method is given for taking into account the effect of biaxial in-plane loading; it depends on a knowledge of the critical buckling load in the longer direction and information for predicting that is included. See also ESDU 94016 and ESDUpac A9416 for program for predicting natural frequencies of orthotropic and isotropic plates including the effect of any combination of shear and direct in-plane loading.