Interface Waves In Prestressed Piezoelectric Layered Structure With Surface Damage Elastomer

With the development of the surface acoustic wave(SAW),nondestructive evaluation using different ultrasonic waves in modern industries and medical fields has been paid more attention by many researchers.Since piezoelectric materials have positive and anti-piezoelectric effects,many researchers study the propagation characteristics of surface acoustic waves in different piezoelectric structures with subsurface damage,providing theoretical guidance for nondestructive testing.In this paper,we investigated the propagation characteristics of interfacial waves in prestressed piezoelectric layered structures with sub-surface damage based on the basic theory of elastic dynamics.The main contents of this paper are as follows:Firstly,this paper reasonably assumes that the material parameters in the subsurface damage layer exhibit a "gradient" variation along the thickness direction.The propagation characteristics of horizontal shear interface waves in prestressed piezoelectric layered structures with sub-surface damage are studied by power series method.Based on the constitutive equation,geometric equation and pre-stressed equation of motion,we derive the field control equations with respect to the displacement function and the electrical potential function,we obtain the dispersion equation of the SH interface wave by combining the boundary conditions and the attenuation conditions.The results show that horizontal shear interface waves can propagate in this structure.The relation between wave number and wave velocity and the distribution of displacement amplitude,potential amplitude,and stress amplitude are illustrated.Numerical examples reveal the horizontal shear interface wave to have a normal dispersion.The more serious the subsurface damage is,the lower the phase velocity is.Secondly,based on the above model structure and research methods,we study the propagation characteristics of generalized Stonely waves in prestressed piezoelectric layered structures with sub-surface damage.The results show that generalized Stonely waves can propagate in this structure and have a normal dispersion.The larger the gradient parameter p,the smaller the phase velocity is.The influence of the frequency-thickness product and gradient parameters on the displacement amplitude and potential amplitude of the generalized Stonely wave is analyzed and discussed.It is found that the propagation characteristics of interface waves in piezoelectric layered structure with sub-surface damage under pre-stress can provide theoretical basis and guidance for ultrasonic nondestructive testing of piezoelectric layered materials.