Optimized Dynamic Acousto-elasticity Applied to Fatigue Damage and Stress Corrosion Cracking

Modeling nonlinear viscoelasticity in dynamic acoustoelasticity

“…This method has already been demonstrated to be relevant and sensitive to nonlinear elastic and hysteretic responses, particularly when characterizing the aforementioned complex media: granular media, 13,14 ultrasound contrast agents, 15,16 and micro-damaged solids (rock samples, [17][18][19] bone tissues, 20 metals, 21 and concrete 22 ). The different nonlinear hysteretic shapes of the acoustoelastic responses ( Figure 2) motivate us to consider the nonlinear viscous effects in addition to more standard nonlinear elastic contributions.…”

Investigation of the validity of Dynamic AcoustoElastic Testing for measuring nonlinear elasticity

“…As a consequence, a scalar value of the nonlinear parameters b and d is in general given. 22,[28][29][30][31] These scalar values are therefore an estimate of a complex function of the components of the tensorial nonlinear parameters.…”

Continuous waves probing in dynamic acoustoelastic testing

“…To have a direct measurement of the stress-strain relation without quasi-static testing and in the low tensilecompressive strain regime, the dynamic acoustoelastic testing (DAET) has been proposed. [31][32][33][34][35] The method is conceptually simple: a high amplitude and low frequency (LF) wave is used to excite continuously the sample (pump), while a high frequency (HF) pulse with small amplitude (probe) is used to measure the modulus, extracted from timeof-flight (TOF) measurements. If the probe is injected in the sample at different phases of the pump, it monitors the values of the elastic modulus at different strains, since the pulse propagates in a medium stressed by the wavefield due to the pump.…”

“…Following the same approach used by other authors, [31][32][33] the curves reported in Fig. 3 could be fitted with a parabolic approximation in the form…”