Topology optimization of Prager structures based on truss-like material model

A finite element method is presented to optimize Prager structures using a truss-like material model. The members are assumed to be distributed over the design domain continuously but non-uniformly, and their densities and orientations at nodes are taken as design variables. The initial loads are applied to the design domain uniformly, and the densities of members are optimized by fully stressed criteria, with the members aligning along the principal direction of stress. Concomitantly, loads are moved to the elevations of the centroid along the vertical direction. Through iterating the above procedure until convergence, Prager structures can be optimized into anisotropic structures in which most of the arches are not parallel to each other.