The PVA/Si composite was prepared by casting method, the weight of PVA is constant
(1gm) while the Si powder were (0.02, 0.04, 0.06, 0.08) gm, the densities of the samples were
measured in the weight method. In order to evaluate the mechanical properties of PVA/Si composite
the ultrasonic measurements were performed at the samples , these properties are ultrasonic
velocity, compressibility, acoustic impedance and bulk modulus, absorption coefficient, the
relaxation amplitude and transmittance were analyzed at different frequencies (25 and 30) kHz. It
was found that there is significant relationship between ultrasonic velocity and density on the
material mechanical properties.