ESDU 85012:2012

ESDU 85012 introduces a computer program for the estimation of
the material damping in a rectangular, laminated plate, with
simply-supported or clamped edges, vibrating in the lower frequency
natural modes (up to the fifth mode). The procedure applies when
laminae having the same material properties and orientations of
their principal axes of orthotropy are symmetrically disposed about
the mid-plane of the plate. Beam characteristic functions are used
to define the mode shapes, and the analysis sums the contributions
to energy dissipation from each lamina. The input includes
individual lamina elastic properties, the calculation of which is
treated in ESDU 83035, and damping properties. Curves are given to
enable approximate values of damping in longitudinal and transverse
flexure and in longitudinal shear to be estimated for each lamina.
Guidance is given on the effect of various factors on the damping
of fibre-reinforced laminated plates, and a practical worked
example illustrates the use of the method. The program is available
as ESDUpac A8512.