Design for manufacture of optimal compliant topologies with honeycomb continuum representation

We present and compare two approaches to obtain optimal binary designs of compliant mechanisms that can be manufactured as is. Honeycomb representation is used to avoid singularities due to checkerboard and point flexure pathologies that appear in square cell based discretization of the domain. A Hex cell accurately models displacement and stress fields especially when approaching its non-existing state which is contrary to its square cell counterpart. In the first approach, sigmoid material interpolation function is employed with a gradient based strategy that poses topology design as a limiting case of size optimization. Though this technique shows promise in obtaining binary designs, the latter cannot always be guaranteed. The other approach based on stochastic search decouples topology optimization from size optimization and uses a novel material mask overlay strategy that ensures optimal binary design and can be manufactured without any post processing.