Singularity At Axisymmetric Interface Wedge Of Bonded Dissimilar Transversely Isotropic Piezoelectric Materials Considering Dimension Effects

Interfaces are important microstructures of piezoelectric composites. Many axisymmetric interface wedge and axisymmetric cylindrical interface cracks exist in the structures of piezoelectric composites, and these usually become the initial damage points, as a result of the singular stress field and the singular electric displacement field near the axisymmetric interface wedges, the parameters such as the order of stress singularity and the order of electric displacement singularity, the angle function of stress and electric displacement, and the coefficient of stress intensity must be resolved, in order to find reliable evaluative method which apply to piezoelectric composites.An eigenvalue method was proposed to study the singular stress field and the singular electric displacement field at the axisymmetric interface of the piezoelectric composites. The major work of this paper is as follows:Based on the fundamental equations of the special axisymmetric proble of the transversely isotropic piezoelectric materials and the first-order approximation assumption, the discrete characteristic equation was derived by using of the displacement functions and electric potentia functions with separated variables and the meshless method. The eigenvalue is relative to the order of stress singularity and electric displacement singularity, and the associated eigenvector is with respect to the stress angular variations and electric displacement angular variations. The order of stress singularity and electric displacement singularity, the associated displacemet,the electric displacement,the stress and the electric potential angular variations was obtained.The influences of dimensionless parameterδ, which denoting the ratio of the distance to interface wedge to the sigular dominated region were discussed. The results show: when the ratio is more than two orders of magnitude, the parameters obtained by eigenvalue method are in good agreement with those by first-order approximation, when the ratio is less than two orders of magnitude, the parameters obtained by first-order approximation can not describe the singular stress and electric displacement near the singularity points, and then the influences ofδmust be considered.