Isogeometric Shape Optimization of Auxetics with Prescribed Nonlinear Deformation

Graphical Abstract (from Publication 2 below):

Abstract:

Auxetic materials with negative Poisson’s ratio have potential applications across a broad range of engineering fields. Several Finite Element (FE) based design techniques have been developed to achieve auxetic materials with targeted effective properties, mostly in the linear deformation regime. The FE-based structural optimization frameworks can be timeconsuming because of the need to ensure proper integration between the geometrical description and the corresponding FE analysis, during an iterative design process. In this work, isogeometric shape optimization frameworks based on sensitivity analysis and genetic algorithm developed for the design of 2D auxetic materials over large strain internals are presented. The versatility of these frameworks will be illustrated through the optimization of smoothed petals and missing rib auxetic structures under different loading conditions over very large strains. In the framework, the manufacturability of specimens is ensured by imposing spline-based geometric constraints. In the end, validation of the optimization framework through material property measurement, additive manufacturing, and experimental verification on the final optimized designs is performed.