Influence of Weak Interlayer Bonding on the Thermoelastic Creep Response of a Multi-layered FGM Porous Cylinder

A rotating Multi-layered porous hollow long cylinder with imperfect bonding made of functionally graded material (FGM) was considered. The creep evolution problem was solved analytically for it. It was subjected to thermoelastic loads as well as a Winkler elastic foundation. The stress-strain relation and equilibrium equation were used to obtain a differential equation containing creep strains. First, an analytical solution was presented for the primitive condition ignoring the creep strains. Next, time-dependent stress and displacement rates were achieved by supposing fixed thermo-mechanical boundaries. Finally, an iterative procedure was used to find the history of creep stresses and deformation. Also, the effect of key parameters such as grading index, porosity, bonding imperfection, elastic foundation, and thermal loading was investigated in some numerical examples. The results show the significant effect of grading index and imperfect bonding in the creep response of smart multi-layered cylinders.