Pump and probe waves in dynamic acousto-elasticity: Comprehensive description and comparison with nonlinear elastic theories

摘要: Standard nonlinear ultrasonic methods such as wave frequency mixing or resonance based measurements allow one to extract average, bulk variations of modulus and attenuation versus strain level. In contrast, dynamic acousto-elasticity (DAE) provides the elastic behavior over entire cycle including hysteresis memory effects, detailing full under tension compression. this work, we address experimental difficulties apply new processing methods, illustrating them with a Berea sandstone sample. A projection procedure is used analyze complex signatures harmonic content. Amplitude dependences content are compared existing models. We show that combination classical hysteretic models capture most observed phenomena. Some differences between data highlighted, however. progressive decrease power-law amplitude dependence found for harmonics larger than second strains 10−6. This observation related phenomenon acoustic conditioning brings material metastable state each excitation amplitude. Analysis steady-state regime additional information regarding conditioning, i.e., odd during time log(t)-dependence. confirms affected by conditioning. Experimental challenges addressed include fact compressional mode DAE can be bending/torsion modes: their influence evaluated, guidances given minimize effects.