Reusable and efficient energy-absorbing architected materials via synergy of snap-through instability and inter-locking mechanism

Reusable energy-absorbing materials of high energy dissipation capacity and low rebound force are highly desirable in engineering and daily life. In this work, we design a new type of architected materials consisting of elastic tilted beams and trapezoidal inter-locking structures (ILSs). The tilted beams buckle elastically and snap from undeformed state to a higher-energy state under compression. They are squeezed into the space between ILSs and locked at this configuration when the external load is removed. The energy applied to the structure turns into elastic strain energy of the beams and ILSs, as well as heat generated by friction and snapping motions. This strategy reconciles the conflict between loading bearing capacity and bistability of the structure. The tilted beams are tuned to increase the load they can sustain, and the ILSs are designed to lock the tilted beams. Compared to a counterpart without ILSs, our strategy expands the design space of energy-absorbing architected materials and improves the energy-absorbing capacity greatly. This work opens opportunities for designing reusable and efficient energy-absorbing materials for applications like sports protective equipment and packaging of delicate objects.