Flexoelectric Effect on SH-Wave Propagation in Functionally Graded Fractured Porous Sedimentary Rocks with Interfacial Irregularity

Purpose The present paper focuses on the propagation behaviour of Shear Horizontal (SH) waves in a fluid-saturated func-tionally graded fractured porous material layer consisting of sedimentary rocks perfectly bonded to an irregular piezoelectric semi-infinite substrate with flexoelectric effect. Two distinct cases corresponding to two differently shaped irregularities, viz. rectangular and parabolic, are considered at the layer-substrate interface. Methods With the help of Fourier transform, inverse Fourier transform, and perturbation technique, complex frequency relation has been derived for each type of irregular interface. Two different flexoelectric materials, viz. Lithium niobate (LiNbO3) and Barium titanate (BaTiO3), are taken into account for performing comparative graphical analysis.Results Obtained frequency relations are dissociated into real and imaginary components representing the dispersion and damping of SH-wave propagation. Dispersion and attenuation characteristics of SH-waves are executed graphically on the basis of several key parameters, such as irregularity, functional gradient, flexoelectric coefficient, volume fraction of matrix and fracture pores, piezoelectric, and dielectric constants.Conclusions On applying the referred conditions, the dispersion equations for both type of irregularities fairly match with the Classical Love wave equation. This fact validates the consideration of the layered composite structures. The noteworthy effects of the key parameters on the dispersion and damping of SH-waves are revealed graphically. Moreover, the phase and damped velocities of SH-waves are observed to be significantly greater for LiNbO3 than for BaTiO3 in each irregular case.