Hence, in order to determine the mathematical description of the dynamic modulus by ultrasonic direct test the following properties are considered: specimen geometry (height h and diameter d), as well as its mass (W) and Poisson’s ratio (n) of the material, which will depend on reference temperature at which the test is being performed [1–3]. Likewise, knowing the effective transmission time of the longitudinal waves, it is possible to calculate the sample propagation speed using the following equation: