An elastic-boundary-controlled framework for on-demand stability switching in bistable curved beam metamaterials

This study presents a framework for on-demand stability switching in bistable curved beam metamaterials through the control of elastic boundaries. Theoretical model is derived to quantify the relationship between boundary stiffness (axial and transverse) and key performance metrics, including negative stiffness, bistability, and hysteresis characteristics. A bistable structure with designable axial and transverse elastic boundaries is developed. Theoretical model and experimental results demonstrate that adjusting axial elastic boundaries enables precise transitions between bistable, negative-stiffness, and monostable states, while transverse elastic boundaries govern hysteresis behavior and energy dissipation efficiency. Meanwhile, the synergistic interaction between axial and transverse elastic boundaries, combined with nonlinear elastic constraints, further enhances tunability, achieving controllable localized dissipation phenomena and a 10.7% increase in maximum energy dissipation efficiency compared to linear elastic boundaries. This work lays the foundation for programmable multistable metamaterials from the perspective of elastic constraints, with potential applications in energy-adaptive structures, soft robotics, and mechanical logic systems.