Influence of initial geometric imperfections and porosity on the stability of functionally graded material plates

ABSTRACT

In the present paper, the effect of initial geometric imperfections and porosity on the stability of functionally graded material (FGM) plates is investigated. The formulations are based on the recently developed nonpolynomial higher order shear and normal deformation theory by the authors. The present theory accounts for a nonlinear variation of in-plane and transverse displacement across the thickness. Accountability of thickness stretching effect using only four unknowns makes it distinct from the existing renowned theories. The generic imperfection function is used to model various possible initial geometrical imperfections such as sine-type, local-type, and global-type imperfections. An efficient C⁰ finite element is used for the model and the variational approach is utilized to derive the fundamental equations for the FGM plates. Extensive numerical studies have been conducted to bring out the influence of geometric imperfection, porosity, geometric configuration, and volume fraction index on the stability of FGM plates.

KEYWORDS:

• Geometric imperfection
• nonpolynomial higher order shear and normal deformation theory
• porosity
• stability
• thickness stretching effect