Polymer-based architected materials and structures: Geometry, experiments, constitutive modeling, and advanced simulations

Architected materials and structures achieve superior performance beyond the limits of their bulk counterparts by exploiting the topology. Among these, triply periodic minimal surface (TPMS)-based designs are especially promising owing to their smooth geometry, high connectivity, and tunability. When constructed using polymers, they offer low density, environmental stability, biocompatibility, and expanded design flexibility. However, predictive modeling is challenged by complex geometry, fabrication variability, and, in particular, the nonlinear, strain-rate dependent constitutive behavior of polymers. This work addresses these challenges with a proposed rate-dependent viscoplastic constitutive model with multiple internal mechanisms. Material characterization, calibration, and experimental validation are hierarchically performed using dog-bone, unit-cell, and lattice specimens produced via stereolithography (SLA). Efficient large-deformation computations are enabled by Isogeometric Kirchhoff–Love (KL) thin-shell analysis. The comprehensive constitutive model demonstrates robust predictive capability in capturing the full spectrum of mechanical behavior at the material-point level: pseudo-elasticity at small strains, strain softening after “yielding”, strain hardening at large strains, and strain-rate dependence across a full deformation spectrum. Our work elevates the level of modeling and simulation and provides better pathways for reliable design of lightweight, tunable polymeric architected materials and structures.