Fig. 2: Characterization of the smart acoustic textiles.
a, Image of the glass microfibre. The natural drooping state of the fibre illustrates its flexibility and elasticity. The fibre acts as the acoustic waveguide between the \({T}_{x}\) and \({R}_{x}\) PZTs. b, Image of a SISO system with the fibre woven into a black textile substrate. The substrate is composed of a two-thirds cotton and one-third polyester blend. The smart acoustic textile is flexible. c, Plot of \({R}_{x}\) reception versus \({T}_{x}\) transmission peak-to-peak amplitude in the SISO system (without textile substrate) at different signal frequencies. d, Plot of \({R}_{x}\) reception versus \({T}_{x}\) transmission peak-to-peak amplitude in the SISO system (with textile substrate) at different signal frequencies. e, Illustration of the application of external pressing force (FP) by a finger on the SISO system. f, Principle analysis of acoustic energy loss caused by FP. The touch not only causes energy dissipation at the contact point between the finger and fibre, but also increases the contact stress between fibre and yarns, resulting in more energy loss, as reflected by the \({T}_{x}\) amplitude (AT) and \({R}_{x}\) amplitude (AR). g, Plot of \({R}_{x}\) reception peak-to-peak amplitude versus FP. The data has been smoothed with a moving average to highlight the trend. The shaded region indicates higher sensitivity during the initial increase in FP. h, Illustration of bending angle perception by the SISO system. i, Principle analysis of acoustic energy loss caused by the bending. The elastic deformation of glass microfibre increases contact forces between the fibre and yarns, leading to significant acoustic energy loss. j, Plot of \({R}_{x}\) reception peak-to-peak amplitude versus bending angle (α). The shaded region indicates higher sensitivity within this bending angle range. The data in c, d, g and j were collected under static conditions. The oscilloscope used to measure data in c, g and j has a small error (8-bit amplitude resolution, that is, 1/256 of the full scale). Scale bars, 10 mm. Credit: finger icon in f, Freepik.com.
