Snap-through mechanism of a thin beam confined in a curved constraint

•The proposed novel bistable structure generates snap-through rotation under local opposite curvature loading.•Smaller critical loading and lower energy supply are required to drive the snap-through transition of the proposed bistable structure compared with conventional bistable structures with the fixed boundaries.•A theory is proposed to reveal the elusive mechanism behind the snap-through rotary phenomenon based on the principle of minimum potential energy and saddle-node bifurcation, which can predict the critical loading.•A device is designed to output linear displacement based on the proposed snap-through mechanism.•This work provides a new analysis method for bistable structures with movable boundaries and shows broad application prospect in the field of energy harvesters, actuators, motors, pumps and robots. In this work, a novel snap-through mechanism of a thin beam confined in a curved constraint and driven by local loading curvature is investigated. The movable boundaries of the buckled thin beam enable it to output snap-through rotation at a lower energy input than the double-clamped beam structure. A theory is proposed to reveal the snap-through mechanism of the proposed structure based on the principle of minimum potential energy and saddle-node bifurcation, which uncovers the influences of loading positions, length ratio and constraint radius on the critical loading. Both theoretical and experimental results show that the large loading position and small constraint radius correspond to a large critical loading, while the length ratio hardly affects the critical loading. In addition, an experimental device is designed to output linear displacement based on the proposed snap-through mechanism. Due to lower energy input and snap-through response characteristics, the proposed bistable mechanism exhibits great prospects in energy harvesters, actuators, motors, pumps and robots.