Multiscale modeling of composite materials by a multifield finite element approach

We present a multiscale model for composite materials based on the theory of multifield continua. Such a model includes additional fields besides the standard stress and deformation, allowing the representation of microstructures in a continuous medium. The multiscale model was implemented in a new finite element code, MUSCAFE. Numerical examples describing a fiber-reinforced composite material with a porous (microcracked) elastic matrix are presented. We first discuss an uncoupled model, in which the microstructural relaxation does not influence the macroscopic displacement field. Then, the first stage of development of a fully coupled model is described. Here, appropriate coupling tensors describe the interaction between displacement and microstructure at the macroscopic level, thereby reflecting the microscopic interaction laws between microstructural elements and the matrix. The latter laws are derived by a combination of theoretical assumptions and atomistic molecular dynamics simulations.