LAUSR

This article is aimed to study the forced vibrations of double piezoelectric functionally graded material micropipes conveying fluid carrying a moving load based on the flexoelectricity theory and modified couple stress theory. The two micropipes are identical and are connected with each other continuously by visco-Pasternak medium. The top micropipe is traversed by a load and is labeled as the primary micropipe. The bottom micropipe is labeled as the secondary micropipe. Non-classical governing equations together with corresponding boundary conditions based on the Hamilton’s principle are obtained and then solved by differential quadrature and Runge–Kutta methods. The influences of the material gradient index, length scale parameter, potential electrical, visco-Pasternak foundation, fluid velocity, various boundary conditions, velocity of the moving load and flexoelectric effect on the dimensionless dynamic deflections of system are discussed. The results show that the flexoelectric and piezoelectric effects tend to increase/decrease the dimensionless dynamic deflections of the primary/secondary pipe, respectively. In addition, the effects of spring constant, shear constant and damping coefficient of the visco-Pasternak medium on the dynamic displacement of the primary and secondary micropipes are vice versa.