Separation of Damping and Velocity Strain Dependencies using an Ultrasonic Monochromatic Excitation

Precise knowledge of the dependence of elastic modulus and Q-factor on amplitude of excitation is a prerequisite for the development and validation of models to explain the hysteresis observed in quasi-static experiments for various media, i.e. the different deformations at the same applied stress observed when stress change rate is positive or negative. Separation of different contributions to dynamic nonlinearity (e.g those due to non equilibrium effects, often termed conditioning) and independent estimation of nonlinearities originated by the strain dependence of velocity and damping factor are required, which is often not possible with standard approaches. Here we propose and validate a method which, measuring the response of a sample to a monochromatic excitation at different amplitudes, allows fast, continuous and quasi real-time monitoring of the dependence of the material elastic properties on amplitude: dynamic elastic modulus (related with velocity through density) and Q-factor of the mechanical resonances (related with wave amplitude attenuation parameters