DETERMINATION OF THE ELASTIC-CONSTANTS OF MATERIALS, IN THE FORM OF PLATES, BY A FREE-VIBRATION METHOD

The problem of characterizing thin layer ceramic deposited by plasma s praying has led the authors to develop an original means to determine materials, elastic constants by using a free vibration method. This pa per gives an overview of an experimental set-up used for the elastic p roperties measurement of a free circular plate at room temperature or at higher temperature (1000 degrees C). This method is based on analys is of the natural frequencies of vibration recorded by a microphone. I dentification of experimental natural frequencies and modal parameters that characterize the mode shapes, calculated analytically by using M indlin theory, enables the Young's modulus and Poisson ratio of the ma terial tested to be determined. Analytical and experimental results ar e compared over a frequency range from 0 to 20 kHz. (C) 1996 Academic Press Limited