Beam Array Designs for a Cochlea-Inspired Accelerometer for Impact Measurements

Limitations on neuron firing rates restrict the frequency bandwidth of many biological sensory systems. The cochlea overcomes these limitations to hear high frequency sounds through its tonotopic structure and non-synchronous sampling. The cochlea’s tapering basilar membrane serves as a filter bank decomposing an applied sound into its frequency components. Auditory hair cells produce neural impulses at the peaks in the local basilar membrane oscillations resulting in an event-driven, sub-Nyquist rate sampling strategy. These two effects extend the human hearing range to about 20 kHz despite maximum neuron firing rates of just a few hundred hertz. Inspired by this, this paper presents a concept demonstration of an accelerometer and signal compression strategy for high-rate impact events using a similar filter bank approach. A series of clamped-clamped beams will serve as analog analysis filters much like the cochlea’s basilar membrane. This paper focuses on the design and simulation of such a beam array and how the natural frequencies and damping ratios of the beams’ first modes affect measuring a broadband impact excitation.