A novel fully compliant tensural-compresural bistable mechanism

Abstract

Bistable mechanisms, which can maintain two distinct positions without power input, have been widely used for harvesting vibration energy, constructing metamaterials, sensing threshold acceleration, and achieving adaptable damping. In this work, we propose a novel configuration of fully compliant bistable mechanisms called tensural-compresural bistable mechanisms (TCBMs), in which both tensural segments (compliant segments that are subject to combined tensile and bending loads) and compresural segments (compliant segments that are subject to combined compressive and bending loads) are employed. The combination use of tensural and compresural segments makes TCBMs much easier to be tailored for different design requirements. Although compresural segments are incorporated, potential problems associated with buckling can always be avoided by using compresural segments with smaller slenderness as compared to the tensural segments. To facilitate the design of TCBMs, two kinetostatic models are developed by using the beam constraint model and the chained beam constraint model, respectively. Several TCBM designs accompanied with a prototype test are presented to demonstrate the feasibility of the new bistable configuration and the use of the two kinetostatic models.