An accurate determination of the emitted S-wave arrival
time at the piezoelectric receiver of laboratory triaxial cells
is challenging due to the complex preceding P- and S-wave
patterns. To analyze this pattern and decipher the true arrival
time of the emitted S wave, we simulate wave propagation
from the actuator to the receiver. The piezoelectric response
is accounted for, and the electromechanical coupling is solved,
using the spectral finite-element method or approximated using a linear spatial variation of the electric potential over the
actuator to capture the same field over the receiver. The fully
coupled algorithms are validated with 1D simulations and
compared with an exact solution constructed with the method
of characteristics. Simulations for a 2D simplified experimental system indicate the validity of the linear simplification. The
comparison of the simulated results through a section of the
triaxial cell with laboratory calibration data for a steel specimen validates our choice of damping material proxy within the
actuator. A final series of simulations for two orthotropic
shales with different anisotropy axis orientations with respect
to the cell, and two Fontainebleau sandstones with very different VP/VS ratios, is presented. These differences in physical
properties have little impact on the wave pattern at and just
after the arrival of the main S wave. The pattern is influenced
more by the experimental setup geometry and the actuator’s
internal structure than by the nature of the specimen.