Dynamic acousto-elastic test using continuous probe wave and transient vibration to investigate material nonlinearity

A Model for Nonlinear Elasticity in Rocks Based on Friction of Internal Interfaces and Contact Aging

“…A series of DAET experiments investigated the detailed nonlinear behaviour of different rocks (Renaud et al 2012(Renaud et al , 2013Rivière et al 2013Rivière et al , 2015. Longitudinal, shear (Lott et al 2017) and complex flexural deformation from impacts (Eiras et al 2016) have been used as excitation. The response of a single fatigue crack was investigated (Rivière et al 2014) as well as the in situ nonlinearity of soil on the scale of metres using seismic equipment and a vibrator truck (Renaud et al 2014).…”

Nonlinear Coda Wave Interferometry: Sensitivity to wave-induced material property changes analyzed via numerical simulations in 2D

“…In parallel, another class of characterization methods, namely nonlinear acoustic methods, has been actively developed for the non-destructive evaluation of complex materials, given their high and selective sensitivity to nonlinear scatterers such as cracks or delamination, i.e. structural defects [14][15][16]. Interestingly, the elastic nonlinearities originate from internal solid contacts or extremely compliant (relative to the material matrix) elements, e.g.…”

Dynamic Acousto-Elastic Testing

“…The probe signal recorded at the receiver contains the direct propagation signal superimposed with signals produced by reflections and mode conversion within the sample, which makes the analysis difficult. It is preferable to use a continuous probe in case of strong attenuation (e.g., due to multiple scattering and/or absorption) that reduces the amplitude of waves reflected at the sample boundaries [38].…”

“…Indeed, impacting briefly the surface of the structure may select the resonant modes with the most excitability. The quick change of elasticity following the impact is either probed with short US bursts [29] or a continuous monochromatic US wave [38]. The main drawback is the difficulty to characterize the strain field seen by the US probe as multiple resonance modes are simultaneously excited.…”