Abstract:

This method is based on the inverse solution to the vibration problem of a finite elastic cylinder with reinforced torsion surfaces by rigid septa or plates. In all cases the polymer layer to be tested is bonded to rigid plates; therefore, the radial displacement is zero at the boundary between the polymer layer and the septum. The admittance matrix Y of the element with abovementioned boundary conditions is constructed within the framework of the hypothesis for planar cross sections. The dimensionless shear wave number k[inf t]((omega))h and compression wave number k[inf (lambda)]((omega))h, which are the unknown variables, are obtained by measuring the transfer matrix of a known structure and as a result of solving the transcendental equation in a designated frequency range. Data are attained over a broadband of frequencies and temperatures without dependence on the time-temperature superposition principle.