Soniya Chaudhary

Bio: Soniya Chaudhary is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Piezoelectricity & Shearing (physics). The author has co-authored 1 publications.

Enhancing Strain-Sensing Properties of the Conductive Hydrogel by Introducing PVDF-TrFE.

Abstract: Conductive hydrogels have attracted attention because of their wide application in wearable devices. However, it is still a challenge to achieve conductive hydrogels with high sensitivity and wide frequency band response for smart wearable strain sensors. Here, we report a composite hydrogel with piezoresistive and piezoelectric sensing for flexible strain sensors. The composite hydrogel consists of cross-linked chitosan quaternary ammonium salt (CHACC) as the hydrogel matrix, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT: PSS) as the conductive filler, and poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE) as the piezoelectric filler. A one-pot thermoforming and solution exchange method was used to synthesize the CHACC/PEDOT: PSS/PVDF-TrFE hydrogel. The hydrogel-based strain sensor exhibits very high sensitivity (GF: 19.3), fast response (response time: 63.2 ms), and wide frequency range (response frequency: 5-25 Hz), while maintaining excellent mechanical properties (elongation at break up to 293%). It can be concluded that enhanced strain-sensing properties of the hydrogel are contributed to both greater change in the relative resistance under stress and wider response to dynamic and static stimulus by adding PVDF-TrFE. This has a broad application in monitoring human motion, detecting subtle movements, and identifying object contours and a hydrogel-based array sensor. This work provides an insight into the design of composite hydrogels based on piezoelectric and piezoresistive sensing with applications for wearable sensors.

Two Dimensional Finite Difference Model with a Singularity Attenuation Factor for Structural Health Monitoring of Single Lap Joints

Abstract: A finite difference algorithm that evaluates the health conditions of a bonded joint is presented and discussed. The mathematical formulation of the problem is developed, paying particular attention to the singularity around the corners of the joint and implementing an original discretisation method of the partial differential equations governing the propagation of the elastic waves. The equations are solved under the only hypothesis of a bidimensional field. The algorithm is sensible to defects in the bonded joint and can be used as an effective structural health monitoring tool, as proven by the experiments that show close agreement with the numerical simulations.

Effect of initial stresses on the surface wave propagation in highly anisotropic piezoelectric composite media

Abstract: The present work analyses the propagation phenomenon of the Rayleigh wave in a piezoelectric-orthotropic substrate beneath a piezoelectric-orthotropic layer under the influence of initial stresses. The dispersion equations of Rayleigh wave propagation on the considered composite structure are obtained by employing suitable non-traditional boundary conditions for electrically open circuits and electrically short circuits. The data of two different PVDF materials have been considered to investigate the latent characteristics of Rayleigh wave propagation in the considered structure. Numerical calculations have been carried out to study the impact of initial stresses on the phase velocity of Rayleigh wave against wave number in all the considered directions of wave propagation for both electrical cases. A comparative study has also been carried out to unfold the impact of initial stresses in all the directions of Rayleigh wave propagation in electrical open- and short-circuit cases and manifested graphically. The obtained result is well-matched with the classical case of the Rayleigh wave for validation and is discussed as one of the problem's special cases. This study may help to improve the design of electrically generating and detecting acoustic devices.