A Simple Analytical Model for MEMS Cantilever Beam Piezoelectric Accelerometer and High Sensitivity Design for SHM (structural health monitoring) Applications

Abstract

Cantilever beam MEMS piezoelectric accelerometers are the simplest and most widely used accelerometer structure. This paper discusses the design of a piezoelectric accelerometer exclusively for SHM applications. While such accelerometers need to operate at a lower frequency range, they also need to possess high sensitivity and low noise floor. The availability of a simple model for deflection, charge, and voltage sensitivities will make the accelerometer design procedure less cumbersome. However, a review of the open literature suggests that such a model has not yet been proposed. In addition, previous works either depended on FEM analysis or only reported on the fabrication and characterization of piezoelectric accelerometers. Hence, this paper presents, for the first time, a simple analytical model developed for the deflection, induced voltage, and charge sensitivity of a cantilever beam piezoelectric accelerometer.The model is then verified using FEM analysis for a range of different cases. Further, the model was validated by comparing the induced voltages of an accelerometer estimated using this model with experimental voltages measured in the accelerometer after fabrication. Subsequently, the design of an accelerometer is demonstrated for SHM applications using the analytical model developed in this work. The designed accelerometer has 60 mV/g voltage sensitivity and 2.4 pC/g charge sensitivity, which are relatively high values compared to those of the piezoresistive and capacitive accelerometers for SHM applications reported earlier.

A miniaturized acoustic vector sensor with PIN-PMN-PT single crystal cantilever beam accelerometers

“…High compliance of the cantilever beam structure allows highly sensitive measurement of the base motion and a light proof mass to have a desirable resonance frequency. Also, the simple structure with a compact size has advantages [17,18]. Figure 1a shows a bimorph cantilever beam accelerometer with a proof mass at the tip and a piezoelectric layer on top and bottom of the elastic substrate.…”

“…The pressure sensitivity and signal-to-noise ratio of a bimorph cantilever beam vector sensor for various piezoelectric materials is plotted against frequency in Figure 2. Since the response around the resonance frequency is closely related with damping rather than piezoelectric material properties, the sensitivity and signal-to-noise ratio are calculated with low-frequency assumption by using equations (17) and (18). The cantilever beam is 4.0 mm in width and 7.0 mm in length.…”

Fabrication and Characteristic of a Double Piezoelectric Layer Acceleration Sensor Based on Li-Doped ZnO Thin Film

“…As very important inertial sensors, acceleration sensors are extensively used in the military [10] and industrial [4] and commercial applications [11]. Piezoelectric acceleration sensors, also important, are widely used in many applications, such as flexible devices [11,12], structural health monitoring [13], seismic exploration [14], and biomedical products [15].…”

A Mathematical Model of a Piezo-Resistive Eight-Beam Three-Axis Accelerometer with Simulation and Experimental Validation

“…According to their different principles of sensing acceleration, MEMS accelerometers can be divided into piezo-resistive, piezoelectric, capacitive, etc. [ 7 , 8 , 9 ]. A comparison of the three types of accelerometers is shown in Table 1 .…”