Global-local analysis of large-scale composite tructures using finite element methods

Large domain design problems using finite element methods (FEM) require special techniques to achieve solutions within reasonable computational time. Global-local FEM refers to a set of numerical techniques designed to reduce the total solution time (and therefore the computational effort) for a given level of solution accuracy. In this paper we address the solution to large-scale periodic structures made up of multi-material composite systems, using two different global-local techniques. An error analysis is performed where the spatial distribution of errors due to material discontinuities and numerical solution procedures are evaluated for both of the methods. A simple illustrative example is used in which the error is quantified in relation to the savings in computational time. The two methods are then applied to the design of a high-field hybrid magnet, an axi-symmetric composite structure made up of a periodic array of "unit cells".