Towards closed-walled designs in topology optimization using selective penalization

Abstract 3D topology optimization using a density approach with penalization usually produces truss-like, open-walled structures. The coarser the mesh, smaller volume fraction, and faster is increased, more pronounced this effect tends to be. However, closed-walled designs are often efficient have other beneficial properties. For instance, closed walls can contribute achieving self-supporting for additive manufacturing that potentially require fewer sacrificial support structures than truss-like designs. This paper presents two-step procedure generating coarse meshes. first step takes usual Eulerian of performing SIMP-based on fixed mesh. To keep thin geometrical features, like thickness below element size, switched off deliberately where formation such features detected. Adopting Lagrangian description, intermediate densities still present in optimized design subsequently eliminated second by shrinking each according its density. By analogy volumetric thermal contraction, accomplished solving fictitious thermo-elastic problem temperature has been replaced expression. outcome morphed mesh somewhat smoothed surface close specified material limit. body-fitted representation considerably simplifies final conversion into manufacturable CAD-type geometry. applied cantilever, torsion rod, disk reinforcement benchmark problem. Optimized show very good agreement those found much finer Problem-specific stiffness improvements over between $$6\%$$ 6 % almost $$30\%$$ 30 were achieved confirmed findings previously reported authors.