Residual‐Stress Programming Enables Reciprocal Multistability in 3D‐Printed Architected Materials

ABSTRACT Multistability offers a powerful means to embed adaptability, energy management, and mechanical memory in architected materials. Achieving symmetric and reversible bistability, however, requires precise control of internal stress fields—a capability that remains inaccessible to current additive manufacturing approaches. Here, we introduce a residual‐stress programming strategy based on controlled thermal cycling that exploits transient viscoelastic relaxation to deterministically stabilize reciprocal energy landscapes in 3D‐printed architected solids. The approach enables geometry‐preserving, symmetric bistability in monolithic printed structures, independent of hinges, multimaterial interfaces, or manual assembly, which are typically required to realize multistable architectures. Finite element simulations and reduced‐order models capture the coupling between differential cooling dynamics and elastic buckling onset, linking stress evolution to bistable equilibria. We demonstrate this principle in both lattice‐ and shell‐based metamaterials that exhibit sequential, layer‐by‐layer energy dissipation under impact loading. Together, these results establish a general framework for programming robust multistability into architected materials, enabling new opportunities in energy management, mechanical computing, metamaterials, and soft robotics.