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190 ALEKSANDR KORJAKIN ET AL.
Figure 9. Modal loss factors of the sandwich cylindrical panel for modes 1 – 1–1 – 4.
Vibration and Damping Analysis of a
Composite Sandwich Conical Shell
A three-layered composite conical shell has been considered. The shell has two
variants of boundary conditions: clamped-clamped and simply supported-simply
supported from both sides. The following geometric characteristics are presented:
the thickness of outer layers h t = 0.0005 m and core h c = 0.004, 0.005, 0.006, ...,
0.012 m, the radius of the cone at its small end R = 0.27 m, the semi-vertex angle
β = 7.0°, the meridional length of the cone L = 0.84 m, Figure 6. The layers are with
the following properties of material: outer from glass epoxy E t = 25.0 GPa,
ν t = 0.20, p t = 2800 kg/m 3 and inner from aluminium honeycomb E1 c =0.529 GPa,
E2 c c c
= 0.226 GPa, ν 12 = ν 23 = 0.2, ρ c = 36.80 kg/m 3 . The loss factor was assumed
zero (η t = 0) for outer layers and η c = 0.4 for the core. The results for the natural frequencies
and modal loss factors of sandwich conical shell with different core
thickness obtained by using finite element CLW54 are presented in Figures 10 and
11 for clamped-clamped and Figures 12 and 13 for simply supported boundary
conditions.
Vibration and Damping Analysis of
Composite Sandwich Spherical Shell
A three-layered composite spherical shell has been considered. The shell is