The purpose of this paper is to present an original means to determine materials elastic constants using a free vibration method. This experimental device enables us to obtain the natural frequencies of a free circular plate subject to heating at temperatures ranging from 20 to 1000 °C. The vibrations of the sample are recorded by a microphone. The identification of experimental natural frequencies is obtained by comparison with frequency spectrum resulting from two experimental means. A grid method consists in determining the elastic constants of the materials by comparing the experimental frequency with the frequencies calculated analytically using Ritz method.