COMPARISON BETWEEN PREDICTION AND MEASUREMENT OF VISCOELASTIC MODULI IN COMPOSITE-MATERIALS VERSUS TEMPERATURE USING ULTRASONIC IMMERSION TECHNIQUE WITH OIL

An oil immersion ultrasonic method used for measuring elastic and visc oelastic properties of materials versus temperature is presented. From velocity and amplitude measurements, the complex viscoelastic tensor can be entirely determined from room temperature to temperatures near the glass transition temperature of the material. This tensor permits the computation of velocities and attenuations of heterogeneous or hom ogeneous modes in any direction of wave propagation. A micromechanics model is used to compare experimental results with theoretical ones an d to analyze anisotropic elastic and viscoelastic behavior of composit e materials, (C) 1997 Acoustical Society of America. [S0001-4966(97)01 112-0].