High performance MEMS accelerometers for concrete SHM applications and comparison with COTS accelerometers

• Little existence of Micro Electro Mechanical Systems (MEMS) accelerometers for Structural Health Monitoring (SHM).
• Acceleration sensing, signal processing and communication electronics integration possible by MEMS technology.
• High sensitivity, low noise floor and small bandwidth smart acceleration sensor for SHM – A challenge as on date!.
• Exclusive design of bulk micromachined piezoresistive and surface micromachined capacitive accelerometers for SHM applications is the special feature of this research.
• Performance comparison with commercial MEMS accelerometers establishes the superiority of the reported devices.

Accelerometers used for civil and huge mechanical structural health monitoring intend to measure the shift in the natural frequency of the monitored structures (<100 Hz) and such sensors should have large sensitivity and extremely low noise floor. Sensitivity of accelerometers is inversely proportional to the frequency squared. Commercial MEMS (Micro Electro-Mechanical System) accelerometers that are generally designed for large bandwidth (e.g 25 kHz in ADXL150) have poor sensor level sensitivity and therefore uses complex signal conditioning electronics to achieve large sensitivity and low noise floor which in turn results in higher cost. In this work, an attempt has been made to design MEMS capacitive and piezoresistive accelerometers for smaller bandwidth using IntelliSuite and CoventorWare MEMS tools respectively. The various performance metrics have been obtained using simulation experiments and the results show that these sensors have excellent voltage sensitivity, noise performance and high resolution at sensor level and are even superior to commercial MEMS accelerometers.