New state-space approach to dynamic analysis of porous FG beam under different boundary conditions

This paper investigates dynamic behavior of porous functionally graded beams under various boundary conditions using State-space approach. The material parameters of FG beams change continuously along the thickness direction according to the power-law function (PFGM) or sigmoid function (SFGM). The porous FG beams are assumed to have even and uneven distributions of porosities over the beam cross-section. The classical beam theory, first-order and higher-order shear deformation theories are employed to consider beams of various boundary conditions. Hamilton's principle are employed for derivation of the equations of motion. Fundamental frequencies are calculated numerically for different boundary conditions, gradient index, volume fraction of porosity, distribution shape of porosity, and span-to-depth ratios. The results show that the variation of the distribution shape of porosity has an effect on the fundamental frequencies.