Using sound in the very near field of vibrating plates for determination of their mechanical properties

During the evaluation of Young’s modulus by vibroacoustic methods, it is usually assumed that Poisson's ratio known. This assumption based on a reasonable tolerance methods to an inadequate estimate ratio. However, most studies do not consider influence error in estimation Young's error. Moreover, total typically does include any parametric analysis at all. Therefore, new method proposed provides simple and reciprocal determination The measurements natural vibration modes elongated plates using scanning microphone very near field. results sound pressure are interpolated with quadratic harmonic function improve spatial resolution locating nodes. advantage this can be calculated directly measuring wavelength bending wave. otherwise much more difficult measure than modulus. used determine various polymers, wood, composites. compared standardised ASTM 1875 “Standard Test Method for Dynamic Modulus, Shear Ratio Sonic Resonance”. show accuracy mainly influenced material density measured sample thickness. these two parameters also has dominant its demonstrated three different plates: aluminium, steel soft plexiglass. aluminium were those obtained method. smaller given experimental conditions.