Bi-Stability in Flexure Beams: Introducing a Setup for Experimental Characterization

Abstract

Bi-stable mechanisms can remain in two positions without a power input or locking system. These mechanisms can achieve large displacements with low energy, requiring power only during switching. However, their design and analysis are challenging due to the non-linear behavior of their flexible members. Researchers commonly use experimental approaches to study and validate bi-stability, which demands efficient and affordable setups. This work presents a versatile and easy-to-fabricate setup to investigate the bi-stable behavior of flexure beams made of styrene plastic. The testing setup is made of laser-cut acrylic connectors and 3D-printed fixtures. The experiments demonstrate that all tested beams are bi-stable and highlight the impact of thickness on their behavior. The critical forces obtained range from 0.0277 N to 5.2724 N between the thinnest and the thickest samples. The distance traveled before snapping increments, with thickness, ranges from 18.78 mm to 32.6 mm. The samples were subjected to a cyclic compressive load and demonstrated a considerable decrement in the critical forces after the first load. Thicker flexural beams present a more significant deformation, causing fractures in some cases after the five loads. Regardless of the thickness, all samples traveled the same total linear displacement of 45 mm. The presented setup demonstrated consistency and rapidness in experimental bi-stability characterization, with the styrene plastic flexure beams proving to be suitable for studying bi-stability.