Propagation of Bleustein–Gulyaev waves in a prestressed layered piezoelectric structure

Sound in biased piezoelectric materials of general anisotropy

“…This optimization procedure is more accurate than the procedure of Liu et al [13], where, for the case of surface waves on biased piezoelectric crystals, in (12)- (14), only the initial value e initial kl obtained from (15) is used, instead of the exact result [e 0 kl ]. Nevertheless, according to [18,19] for stressed anisotropic materials (here extended to piezo-electric materials), one must add an extra term to (3), i.e.…”

“…In the paper of Liu et al [13], the second term on the right side of (17) is not explicitly taken into account, whilst according to Man and Lu [19] this term should be taken into account for generality (e.g for including plasticity due to the bias stress). This extra term is always taken into account in the calculations reported in the current paper.…”

“…The relations are calculated by a newly developed semi-automatic computer program that is able to handle any kind of symmetry relations and the results differ from the ones of [37,38], where a trigonal 3m crystal is considered, instead of the trigonal 3m crystal of the current report. The developed computer program uncovered one misprint in the material property tables in [13].…”

“…Lately, possibly with the purpose of measuring stress or with the purpose of controlling actuators [10][11][12] by means of stress, the propagation of surface waves on piezoelectric materials, has been studied [13]. This motivated us to study the propagation of bulk waves in the presence of a bias field and to find out whether the presence of piezoelectricity makes a crystal more or less susceptible to stress and also to find out how inhomogeneous waves behave in biased piezoelectric crystals.…”

“…Therefore, we consider sound, described in a linear regime, that is propagating in a crystal whose properties are affected in a nonlinear way by the presence of a bias field. Consideration of this effect has been done before for surface waves [13], though not for bulk waves in these materials. Expressions are obtained for the dependence of the material properties on the bias fields and these expressions are used to obtain a generalized form of the Christoffel equation for general anisotropic (triclinic) media.…”