Functionally graded saturated porous structures: A review

Functionally graded porous materials are porous structures with porosity gradient distributed over volume. The porous structures having valuable properties, such as lightweight and excellent energy absorption, have been considerably used in different engineering implementations such as aerospace, biomedical, and other industries. Two limit cases are usually considered for the porous structures: 1- The fluid pressure of pores is zero and 2- The pores fill by incompressible fluid and is in saturated condition. Many investigations have been reported on the behavior of functionally graded porous structures. But, most of them are concerned on the drained conditions. However, the investigations into saturated porous structures are limited in number. The present paper (a) specially reviews the mechanical properties of functionally graded saturated porous structures; (b) presents a comprehensive review on the mechanical analyses of these structures in saturated condition; (c) discusses the challenges and possible future works.