Abstract
[Display omitted]
•Little existence of MEMS accelerometer for SHM in the present sensor market.•High sensitivity, low noise floor and large bandwidth – A challenge as on date!.•Narrow BW MEMS capacitive accelerometer design satisfies SHM and seismic requirements.•Performance comparison with COTS sensors establishes superiority of sensors presented.
This work presents the design of a MEMS accelerometer that is specifically intended for Structural Health Monitoring (SHM) applications where sensing low frequency low amplitude accelerations with high resolution is essential. The surface micromachined comb drive capacitance accelerometer structure has been considered in this design. The simulation experiments conducted on these devices using IntelliSuite MEMS design tool show that it has excellent displacement sensitivity of 21.39μm/g, a capacitive sensitivity of 1.22pF/g and voltage sensitivity of 1783mV/g/V when it is designed to measure 0–0.1g. Further, it is seen that it has a very low noise floor of 1.32μg/√Hz and therefore high resolution. Since the accelerations can be as low as 0.04g in SHM applications, excellent resolution is the primary goal in this design. Further, one more sensor specifically meant for strong motion seismic application has also been reported. This device has a bandwidth of 0–250Hz and a noise floor of 5.612μg/√Hz in addition to a sensor level voltage sensitivity of 97.9mV/g/V. Finally, the comparison of these results with other similar devices reported in the past clearly illustrates the comparable performance of the present devices. Further, these devices, unlike the commercial low frequency accelerometers and other similar devices reported in the past can be fabricated by surface micromachining and CMOS compatible processes.