Fig. 7: Application of our method to passive signal transformation.
From: Customizable wave tailoring nonlinear materials enabled by bilevel inverse design
a Input (dashed black) and target output (dashed purple) half-cycle sine waves, and the output waves obtained from DEM simulations with linear (solid black) and optimized (solid purple) nonlinear springs. b Force-displacement relations for the pulse shaping (solid purple) shown in (a), in contrast with the previous target of KE minimization (solid red), from DEM-optimization. KE minimization resulted in a snap-through mechanism while the pulse shaping displays a softening-to-stiffening response in compression and stiffening response in tension. Direct polyfit obtained from the FEM shape optimization (a line of purple stars) and the validation of the resultant shape via COMSOL FEM (Finite Element Method) simulations (dashed purple). Circle and triangle markers indicate the maximum displacements in compression and tension, respectively. c Mesostructure shape identified by the optimizer to match the DEM-identified nonlinearity. Source data are provided as a Source Data file.
