A passive micromechanical broadband amplifier for acoustic emission sensing

A novel mechanical amplification mechanism based on a coupled mass-spring system is presented. The mechanism effectively transduces and amplifies structural vibrations within a broad frequency range into out-of-plane motion and needs no electrical power supply. The concept is verified experimentally on two designs consisting of 4 and 8 coupled masses respectively. An average amplification factor of 17.3 (57.8) is achieved for the four (eight) mass design within a bandwidth of 17.3 (6.5) kHz. The proposed mechanism could find uses in ultra-low power detection of weak acoustic or micro-seismic signals for structural health monitoring (e.g. cliffs, buildings and bridges).