Axially Functionally Graded Beams—A Review

Functionally graded material (FGM) structures are innovative designs where material properties vary gradually in one, two or three directions, resulting in enhanced mechanical or thermal properties. The most of work in the literature is devoted to functionally graded structures having variations of properties along the thickness direction (much smaller than the other two directions). However, there are many applications where gradation along the length is required (axial direction). The aim of the paper is to present the state of the art in the field of axially functionally graded (AFG) structures. Here both theoretical and experimental models are discussed in detail. In literature, AFG structures like beam, plate, and shell are analyzed under static, dynamic, and buckling loadings. Recently special kinds of axially functionally graded such as microbeam, microtube, and piezoelectric composite beams are also investigated in the literature. Even after a good amount of theoretical investigations, there is very little work in experimental, manufacturing, and application point of view. There is an urgent need to design, fabricate, and test components for real-life applications.