Xiaoguang Yuan

Bio: Xiaoguang Yuan is an academic researcher. The author has contributed to research in topics: Wave shoaling & Wave vector. The author has an hindex of 1, co-authored 1 publications receiving 6 citations.

Inhomogeneous wave reflection in a rotating piezoelectric body

Abstract: The purpose of this paper is to address the wave reflection over the rotating piezoelectric boundary surface in the framework of inhomogeneous wave theory which can introduce an additional reflected surface wave over the boundary surface to solve the problem of discrepancy between independent wave modes and boundary equations. A set of homogeneous equations in displacements and electric potential is derived within the rotatory coordinate system in the presence of the Coriolis and centrifugal acceleration presenting noticeable influence upon the wave propagation and reflection. Other than the transverse wave, the performed plane example shows that there is a critical point of when angular velocity equals the wave frequency for the quasi-longitudinal wave. The results also reveal that the angular velocity is accompanied by the modification of reflected waves especially in the case of reflected surface mode as well as the reflection angles, the amplitudes, and energy ratio coefficients.

Wave reflection and transmission in rotating and stressed pyroelectric half-planes

Abstract: This paper describes the rotation and initial stress effects on the wave reflection and transmission between two pyroelectric half-planes using inhomogeneous wave approach. The rotation in the governing pyroelectric equation is characterized by considering the Coriolis and centrifugal accelerations and the initial stresses are considered by modifying the elasticity tensor. A scenario is modeled where a quasi-transverse wave is incident on interface, resulting into reflected and transmitted waves like temperature wave, quasi-transverse wave, quasi-longitudianal wave, and surface wave in both half-planes. Rotation and initial stresses’ effects on the wave velocity, attenuation, and energy coefficients are presented.

Surface Acoustic Wave Gyroscopic Effect in an Interdigital Transducer.

Abstract: The surface acoustic wave (SAW) gyroscopic effect in an interdigital transducer (IDT) deposited on a piezoelectric substrate is different from that in the piezoelectric substrate due to a reflection induced by IDT. In this work, an extended coupling-of-mode (COM) model including the gyroscopic effect and the reflection was developed to analyze the SAW gyroscopic effect. First, dispersion characteristics parameters of SAW were fitted according to the data derived using the finite element method (FEM). Then, variations of stop band edge frequency were calculated using the extended COM theory by integrating dispersion characteristics parameters into the COM model. We compared its results with those obtained via FEM analysis to confirm the proposed model’s validity. We found that the variation in stop band edge frequency related to gyroscope effect reached the maximum value with a zero reflectivity value. For split IDT, the sensitivity of gyroscope effect is 0.036 Hz/rad/s with a lower than 1% normalized thickness. Conversely, the value of sensitivity was almost zero for bidirectional IDT and electrode width controlled single-phase unidirectional transducer (EWC/SPUDT).

Rotational Effects on Propagation of Rayleigh Wave in a Micropolar Piezoelectric Medium

Abstract: Abstract In this paper, the governing equations of a linear, homogeneous and transversely isotropic rotating micropolar piezoelectric medium are solved for surface wave solutions. The appropriate solutions satisfying the radiation conditions are obtained in a half-space. These solutions are applied to suitable boundary conditions at the free surface of the half-space. A frequency equation for Rayleigh wave is obtained for both charge free and electrically shorted cases. Using iteration method, the non-dimensional wave speed of Rayleigh wave is computed for relevant material constants modelling the medium. The effects of rotation, piezoelectricity, frequency and material parameters are observed graphically on the propagation speed.

Wave reflection and refraction in rotating and initially-stressed piezoelectric crystals

Abstract: The purpose of this paper is to address the wave reflection and refraction in the rotating piezoelectric crystals subjected to a biaxial, homogeneous stress field. Besides, utilizing the inhomogeneous wave theory enables additional reflected and refracted surface waves to solve the problem of discrepancy between independent wave modes and boundary equations. A set of homogeneous equations in displacements and electric potential is derived within the rotatory coordinate system in the presence of the Coriolis and centrifugal acceleration. The performed plane example shows that there is a critical point when angular velocity equals the wave frequency, at which no quasi-longitudinal wave can be generated, reflected or refracted, and close to which the characteristics of the quasi-longitudinal wave change sharply. In addition, the presence of the Coriolis and centrifugal accelerations demonstrates noticeable influence upon the wave propagation and reflection/refraction, namely the wave velocities and attenuations, the angles of the reflected/refracted bulk waves, the reflection/refraction amplitudes and energy ratio coefficients. The analysis results also indicate that the reflected and refracted waves can transform into the type of surface wave at some incident angles. Finally, compared with the rotation effects, the waves are not sensitive to the initial stresses.

Wave reflection in a rotating pyroelectric half-plane

Abstract: This paper describes the rotation effects on the wave reflection in a pyroelectric half-plane using an inhomogeneous wave approach. The rotation in the governing pyroelectric equation is characterized by considering the Coriolis and centrifugal accelerations. A scenario is modeled where a quasi-transverse wave is incident on the free boundary surface, resulting in reflected waves like temperature wave, quasi-transverse wave, quasi-longitudinal wave, and surface wave. Rotation’s effects on the reflection angle, velocity, attenuation, and energy coefficients of the reflected wave are presented.