Mechanical Performance and Metrolocigal Characterization of Mems Accelerometers and Application in Modal Analysis

MEMS (Micro-Electro-Mechanical-System) technology is providing inertial sensors to industry, with a low cost manufacturing technology and miniature dimensions capabilities (few millimeters). Nowadays MEMS sensors are widely used in low-accuracy level applications (typically in the automotive field), where cost and dimensions are priority advantages. Starting from these considerations chip producers do not focus on the sensors metrological characterization and on a packaging useful for mechanical measurements. Moreover testing costs, much higher than the cost of sensor itself, make a full mechanical testing not so common. Producers mainly focus on the electrical characterization, and anyway not so much care is devoted to the mechanical facts end users have to fight against. The aim of this paper is to give a contribution, investigating the possibility of using MEMS transducers in applications that require higher performances, such as modal testing or structural health monitoring. This paper contains a complete mechanical characterization of some MEMS sensors in comparison with other traditional accelerometers, piezoelectric and servo ones. The purpose of these tests is therefore to determine their performances in different ambient conditions, aimed to their use during experimental and operational modal analysis or in monitoring applications on big civil structures.