Experimentally verified finite element modeling and analysis of a conformable piezoelectric sensor

Abstract

This paper presents development of a three dimensional finite element model for simulations of a conformable piezoelectric sensor utilizing COMSOL Multiphysics. The sensor has a multi-layer structure composed of four circular piezoelectric elements arranged in an array structure laminated on a soft substrate and is capable of providing a strain mapping of soft tissue surfaces for spatiotemporal biokinematic assessment of the facial skin. Here, we provide the finite element method (FEM) for the sensor to predict its electromechanical behavior. This paper studies the effect of the design parameters such as dimensions of the piezoelectric sensor and the substrate on voltage sensitivity and sensor compliance. The FEM model is established to understand the underlying physics and guide the mechanical characterization of the system. The developed model is experimentally verified through two series of tests. The first set of tests involve comprehensive in vitro mechanical testing to provide accurate measurements of strain during compression, stretching, and bending. The second set of tests present in vivo experiments on healthy and amyotrophic lateral sclerosis subjects. The experimentally verified FEM model provides a detailed insight into analyzing the response of the sensor which establishes new design rules for next generations of conformable piezoelectric sensors.

A Conformable Ultrasound Patch for Cavitation‐Enhanced Transdermal Cosmeceutical Delivery

“…In this study, we report a hands-free IFS system, the conformable ultrasound patch (cUSP), with small (0.8 cm 2 ) piezoelectric discs (PZT-Ds) optimally positioned within a conformable poly(dimethylsiloxane) (PDMS) substrate. [49][50][51] Leveraging a conformal platform allows tight control of the relative spacing between the ultrasound source and the curvy target membrane. The resulting cavity provides a 1 mm-deep reservoir space for the coupling fluid medium wherein inertial cavitation, convective mixing, and microjet formation can be induced on the surface of the skin.…”

An Emerging Era: Conformable Ultrasound Electronics

“…Recent developments in mechanical engineering and material fabrication technology have made it possible to realize high‐performance piezoelectric devices in conformable configurations and given them unique prospects for usage in bio‐integrated applications. [ 14,46 ] Piezoelectric conformable electronics, fabricated from ceramics, crystals, composites, [ 7,47 ] thin film, polymers, fibers, [ 48 ] have demonstrated real‐time and continuous signal monitoring and decoding for diverse soft tissue biomedical and healthcare applications, ranging from sensing [ 46a,49 ] to energy harvesting [ 14a,50 ] and human‐machine interactions, [ 51 ] including in understanding body motion, facial motion, [ 5,52 ] skin modulus, [ 15,53 ] heart motion, [ 54 ] gastrointestinal motility, [ 4 ] tactile stimuli, [ 55 ] blood pressure, [ 16b,34 ] and blood flow. [ 35 ] In addition, through quantitative imaging, piezoelectric ultrasound transducers can provide insight into deep tissues and curved organs, improving our understanding of soft tissue illnesses.…”