Approaches for evaluating Young's and shear moduli in terms of a single SAW velocity via the SAM technique

摘要

In ultrasonic material investigations Young's modulus, E, and shear modulus, G, conventionally expressed in terms of the velocities of longitudinal (F_L,) and transverse (V_T) modes, are usually difficult to determine from a single measurement, in particular for scanning acoustic microscopy. Therefore, using Viktorov formula and physically acceptable approximations, we derive simple expressions for E and G in terms of the velocity, V_i, of just one propagating mode (including Rayleigh mode V_R). It was found that (E, G)=(α_i, β_o)_ρV_i~2. The validity of these expressions is successfully tested, analytically and graphically, for a great number of materials representing a large spectrum of densities, 1000 kg/m~3 < ρ < 22 000 kg/m~3, and characterized by a wide interval of velocities, 1400 m/s < V_L < 12000 m/s.