Embedded Microelectromechanical systems (MEMS) for measuring strain in composites

MEMS strain sensors here fabricated and embedded in laminated composites were designed to function as part of a wireless-sensing network. The sensing element, signal conditioning, and telemetry circuitry have been developed to be fabricated on a single silicon wafer. The sensor design and function's most critical feature was the strain transfer between the sensor and composite matrix. Finite element models were developed to investigate various designs prior to manufacture. Two types of sensors, respectively integral to the wafer and thin silicon nitrate beams attached to the wafer only at the beam root, were developed. An overview of experimental data from an extensive series of tests is presented. (Author)