Mechanical Filters for Accelerometers: Design and Metrological Characterization

Accelerometers saturation may occur when measuring mechanical events characterized by a wide frequency bandwidth. The problem usually arises when the mechanical vibration frequency band exceeds the accelerometer bandwidth. Mechanical filtering is then a smart technique to reject undesired contribution above a certain cut-off frequency and avoid transducer saturation. Commercially available mechanical filters exhibit limits, in particular regarding cut-off frequency selection and insertion error. This paper describes a method to realize a mechanical filter that takes advantage of the mechanical link between the vibrating surface and the accelerometer to obtain the user-demanded characteristics for both mono-axial and tri-axial accelerometers. The designed filter frequency response function is first estimated by means of finite elements method simulations, and then experimentally verified. The effects of temperature and aging on filter performances are also presented