The complex Young's modulus of a viscoelastic material may be obtained as functions of frequency from the measurement of relative motions of the two ends of a bar-type specimen. The non-resonance method is usually used to calculate the complex Young's modulus over a wide range of frequency. However, the complex Young's modulus obtained by non-resonance method is not realiable in anti-resonance frequency regions because of the measurement noise problems.
In this study, the effects of measurement errors on estimating the complex Young's modulus are studied in the aspect of sensitivity and the realiable frequency region for a given measurement error level is identified. The usable frequency regions in determining the complex Young's modulus is represented by a non-dimensional parameter formed with the wave length and specimen length.
