Generalized Study on Time-Dependent Creep Analysis of Functionally Graded Thick-Walled Cylinders Under Thermal and Mechanical Boundary Conditions

Abstract A multiscale model has been developed to investigate the creep behavior of functionally graded thick-walled cylinders. Finite element (FE) simulations are employed to evaluate the position-dependent parameters associated with creep constitutive law at the microscale. A macroscopic FE model solves the non-linear boundary value problem to determine the time-varying creep stresses and strains. The framework proposed can predict the creep response of functionally graded pressure vessels based on the constitutive behavior of the creeping matrix, and volume fraction profile. Effective creep properties have been computed using three different micromechanical models and the homogenized creep response and its effect on the macroscopic behavior are compared. Considering the computational expenses associated with the large 3D-finite element models, investigations show that simple 2D-axisymmetric model can “closely capture” the creep behavior in such multiscale methods. Radial variations of constituent volume fractions have significant effects on stress distributions and creep strains histories. The models are beneficial to investigate the choice of material combinations and heterogeneity profiles, thereby reducing cost of materials, fabrication, and testing associated with experimental trials.