On the dynamic response of porous functionally graded microbeam under moving load

Abstract

In this article, the dynamic behavior of functionally graded (FG) microbeams with different porosity distributions and acted by a moving harmonic load is studied. A bi-dimensional FG microbeam with its material properties changing gradually along both the length and thickness directions in a power-law distribution form is presented. Besides, the porosities are distributed evenly and unevenly in the body of microbeams, and the small-scale effect is captured with the help of the modified couple stress theory. The equations describing the motions of the FG microbeam are obtained in the framework of Hamilton's principle in conjunction with the parabolic shear deformation theory. These equations are solved by employing the finite element formulation, which is validated by comparing the fundamental frequency and dynamic response with previous works. The effects of several key factors such as two grading indexes, small scale parameters, porous distribution pattern and volume fraction, as well as moving speed and motivation frequency of the acted load are investigated in detail. It is concluded that the bi-dimensional FG parameters and porous parameter play significant roles in the dynamic response of microbeams subjected to a moving load, which is helpful for the multi-functional and optimal design of microsystems.