Optimal design of bistable circular arc beam with variable thickness

Bistable structures exhibit significant application potential across diverse fields, including robotics, energy harvesting and micro-electromechanical systems. This study proposes a novel strategy for designing and controlling the snap-through behaviour of circular arc beams by leveraging variable thickness distribution. A theoretical model was developed to analyse the instability deformation of circular arc beams with variable thickness distribution under a central concentrated force. The influence of key design parameters such as the number of segments, central angle, thickness ratio and length ratio on the stable states, energy trapping, maximum strain and critical strain of the structure was systematically investigated. The results demonstrate that thickness distribution not only governs the emergence of bistable behaviour but also significantly impacts crucial performance metrics, including the critical load and maximum strain. Building on these findings, the structure was optimized to maximize energy trapping and achieve a predefined deformation sequence. The optimized design showed excellent agreement with experimental data, validating the proposed approach. This study provides a foundational framework for the application of bistable structures in various engineering contexts, offering insights into their design and control for enhanced performance.