Beam accelerometer

摘要

Methods and devices are disclosed for measuring low levels of acceleration caused by low frequency seismic waves. For example, an omnidirectional beam accelerometer configured to measure low frequency waves is disclosed. The omnidirectional beam accelerometer may include three beam acceleration sensors. Each beam acceleration sensor may include a respective mass and a respective beam. Each respective beam may be comprised at least in part of a piezoelectric material. Each beam acceleration sensor may have a ratio of mass density [kg/m3] to beam stiffness [N/m] of at least 4.5×10−5 kg/Nm2. The omnidirectional beam accelerometer may also include a housing to ensure the sensors are operating in orthogonal directions and an interface circuit to interface between the sensor and external circuitry.

主权项

1. An omnidirectional beam accelerometer configured to measure low frequency waves, the omnidirectional beam accelerometer comprising:
three beam acceleration sensors, wherein each beam acceleration sensor comprises a respective beam comprising a piezoelectric material and a respective mass operably coupled to the center of the respective beam, and each beam acceleration sensor has a ratio of a density of the respective mass [kg/m3] to the stiffness of the respective beam [N/m] of at least 4.5 ×10−5kg/Nm2; a housing, wherein each of the three beam acceleration sensors are operably coupled to the housing using knife clamps applied to each respective end of each of the beam acceleration sensors, and each of the three beam acceleration sensors is configured to measure acceleration in a respective orthogonal direction with a cross axis isolation of approximately 40 dB or better; and an interface circuit operably coupled to each of the three beam acceleration sensors, the interface circuit configured to interface the three beam acceleration sensors with an analog to digital (A/D) converter.