Charles Hudin | Searcharxiv

arXiv2020

When Hearing Defers to Touch

Hearing is often believed to be more sensitive than touch. This assertion is based on a comparison of sensitivities to weak stimuli. The respective stimuli, however, are not easily comparable since hearing is gauged using acoustic pressure and touch using skin displacement. We show that under reasonable assumptions the auditory and tactile detection thresholds can be reconciled on a level playing field. The results indicate that the capacity of touch and hearing to detect weak stimuli varies according to the size of a sensed object as well as to the frequency of its oscillations. In particular, touch is found to be more effective than hearing at detecting small and slow objects.

q-bio.NC↗

arXiv2017

Combination of frequency shift and impedance-based method for robust temperature sensing using piezoceramic devices for shm

The influence of temperature is a major problem in Structural Health Monitoring diagnosis using guided waves. In this article, two methods for temperature compensation are used to evaluate the temperature of a structure monitored by Piezoceramic Transducers (PZT). The first one consists in a linear regression of the static capacity of the PZT (computed with the electromechanical impedance) with the temperature. It allows one to determine temperature of a PZT from any impedance measurement. The second method is based on the Modes Frequency Shift (MFS) of the frequency response function (FRF) calculated in a pitch-catch mode with an exponential sweep signal. A linear regression between the MFS and the temperature is settled for most modes and allow the estimation of temperature between two PZT. Experiments on a composite plate monitored by 5 PZT patches showed that a $\pm$2{\textdegree}C degree variation can easily be identified with both methods. Combined together, those two methods could replace actual temperature sensors and bring an efficient improvement for temperature compensation in applications where the temperature variation is heterogeneous on a structure.

physics.app-ph↗