Measurement methods of complex Poissonʹs ratio of viscoelastic materials

The methods of measuring the complex Poissonʹs ratio of viscoelastic materials as a function of frequency are investigated in this paper with special respect to the accuracy of determining the relevant loss factor. The measurement methods are reviewed, evaluated and compared from the point of view accuracy and frequency range. It is shown that some contradictory beliefs on the frequency dependence of dynamic Poissonʹs ratio and the value of loss factor are due to experimental difficulties. It is pointed out that the measurement of two complex moduli, especially the shear and bulk moduli, may be the most effective method to determine the dynamic Poissonʹs ratio and loss factor over a wide frequency range. An example for determining the complex Poissonʹs ratio of a rubber in a wide frequency range is presented.