Free vibration analysis of porous plates with porosity distributions in the thickness and in-plane directions using isogeometric approach

The main purpose of this paper is to study the free vibration of porous square plate, circular plate, and rectangle plate with a central circular hole in the framework of isogeometric analysis (IGA). Generally, the porosity distributions of plates are assumed to happen in the thickness direction. However, the graded distributions of porosity may occur through the in-plane direction of plates. Therefore, porosity distributions along both the thickness direction and in-plane direction are considered in this study. The displacement fields are described by the first order shear deformation theory (FSDT) and the exact geometric models are formulated wholly by non-uniform rational B-spline (NURBS) basis functions, which bear high-order continuity inherently. To ensure the versatility of IGA-FSDT, several numerical examples for isotropic and porous plates with different boundary conditions and various types of porosity distributions are presented. Moreover, some innovative results are presented and discussed, which can be the benchmark data for other algorithm researches. The effects of porosity coefficient, boundary conditions and geometric parameters on the free vibration of porous plates are investigated comprehensively.