A Bistable Threshold Accelerometer With Fully Compliant Clamped-Clamped Mechanism

In the IEEE SENSORS JOURNAL, vol. 7, no. 8, pp. 1102-1109, 2007, we presented an analyzing method for a threshold accelerometer based on the fully compliant bistable mechanism composed of post-buckling beams with both ends fixed. The critical buckling phenomenon and bistability of the compliant buckling structures are considerably suitable for mechanically sensing the threshold acceleration, and eliminating the electrical power needed for retaining the stable state. Based on the bistability of the fully compliant clamped-clamped mechanism, a threshold accelerometer which can sense the threshold deceleration (cutoff acceleration) after being triggered is designed and fabricated in this paper. The accelerometer mainly consists of a contact, an inertial mass, and two parallel clamped-clamped beams with a length of L and an initial angle ¿. A mini rotating test bench is designed to test the sensing capability of threshold acceleration. The threshold acceleration and deceleration for triggering and cutting-off the accelerometer are 9.7 g and -3.1 g in experiments, which deviate from the design values of 10.0 g and -3.0 g with only 3.0% and 3.33%, respectively. The capabilities of accurate threshold sensing and stable state retaining validate the feasibility of introducing the post-buckling compliant beams in designing threshold accelerometers. And, the accordance in the five experiment results also shows that the repeatability and structural simplicity of the designed threshold accelerometer ensure its reliability and applicability in engineering.