A composite, coupled, thin cylindrical-conical shell system made of polyester
resin reinforced by uniformly distributed, chopped, E-glass is analyzed using
Statistical Energy Analysis. Response displacement estimate of the two
subsystems are obtained due the excitation of the cylinder by a broadband white
noise of constant spectral density function. The paper is an attempt to study the
validity of the SEA hypothesis as applied to coupled built-up structures. This is
carried out by the comparison of response estimates of the coupled system in
different 1/3rd octave frequency bands with those obtained from Finite Element
method. The outcome of this work shows that SEA is a powerful tool for the
vibration analysis of coupled systems at high frequencies when the number of
interacting coupled resonant modes is high. Percentage error obtained from the
comparison of results drops sharply as one goes further in frequency. This paper
recommends that the user of SEA must always be aware of the uncertainty of the
results obtained. The uncertainty may arise from the improper selection of
subsystems, coupling loss factors, and the number of interacting resonant modes
of the coupled system.