ESDU 89011:2011

ESDU 89011 introduces a computer program, provided as ESDUpac
A8911, which calculates the lower natural frequencies of
rectangular thin plates (thickness/shorter dimension ratio less
than 0.05), either flat or with shallow curvature (shorter
dimension/radius ratio very much less than unity). The input is
structured to treat fibre-reinforced laminated plates particularly
conveniently, but will also deal with isotropic materials. The
effects of a uniformly distributed in-plane biaxial loading can be
included but, if compressive, should not exceed 30 per cent of the
buckling load. In-plane shear is neglected, as are shear
deformation and rotary inertia, and the method relies on small
deflection, linear plate theory. The program is restricted to
plates in which the shear coupling terms in the stiffness matrix
are zero. The program has been used to illustrate graphically for a
typical laminated plate the effects of varying curvature and of
varying the in-plane loading. The input format is explained in
detail, and a worked example illustrates it and the format of the
output.