Fully coupled thermo-viscoplastic analysis of composite structures by means of multi-scale three-dimensional finite element computations

The current paper presents a two scale Finite Element approach (FE 2 ), adopting the periodic homogenization method, for fully coupled thermo-mechanical processes. The aim of this work is to predict the overall response of rate-dependent, non-linear, thermo-mechanically coupled problems of 3D periodic composite structures. The material constituents implicated in the analyses obey generalized standard materials laws, while the characteristic equations of the problem (balance law, first law of thermodynamics) are expressed and satisfied in both microscopic and macroscopic scales. For the numerical implementation in both scales, the finite element commercial software ABAQUS is utilized in the framework of small strains and rotations. A set of dedicated scripts and a specially designed Meta-UMAT subroutine allow the connection between the macroscopic structure and the microscopic unit cells attached to every macroscopic integration point. The two-scale finite element framework is applied to simulate thermoelastic-viscoplastic materials of complex 3D composite structures, and its capabilities are demonstrated with proper numerical examples. It is worth mentioning that the proposed computational strategy can be applied for any kind of 3D periodic microstructure and non-linear constitutive law