Experimentally and Numerically Validated Analytical Solutions to Nonbuckling Piezoelectric Serpentine Ribbons

Abstract

Emerging stretchable piezoelectric devices have added exciting sensing and energy harvesting capabilities to wearable and implantable soft electronics. As conventional piezoelectric materials are intrinsically stiff and some are even brittle, out-of-plane wrinkled or buckled structures and in-plane serpentine ribbons have been introduced to enhance their compliance and stretchability. Among those stretchable structures, in-plane piezoelectric serpentine ribbons (PSRs) are preferred on account of their manufacturability and low profiles. To elucidate the trade-off between compliance and sensitivity of PSRs of various shapes, we herein report a theoretical framework by combining the piezoelectric plate theory with our previously developed elasticity solutions for passive serpentine ribbons without piezoelectric property. The electric displacement field and the output voltage of a freestanding but nonbuckling PSR under uniaxial stretch can be analytically solved under linear assumptions. Our analytical solutions were validated by finite element modeling (FEM) and experiments using polyvinylidene fluoride (PVDF)-based PSR. In addition to freestanding PSRs, PSRs sandwiched by polymer layers were also investigated by FEM and experiments. We found that thicker and stiffer polymers reduce the stretchability but enhance the voltage output of PSRs. When the matrix is much softer than the piezoelectric material, our analytical solutions to a freestanding PSR are also applicable to the sandwiched ones.

Composites, Fabrication and Application of Polyvinylidene Fluoride for Flexible Electromechanical Devices: A Review

“…Electrospinning is a very promising processing technology. The needle tube containing the After the PVDF film is formed, there are further studies to constrain the nanostructure of the film, such as the serpentine structure [124][125][126] and Kirigami structure [127] formed by cutting plotter, achieving sufficient compliance of mechanical deformation to skin motion. Conversely, the polymer film is cut into the desired shape and then stacked and laminated to increase the density of the filler [128].…”

Nonlinear Mechanics of Beams With Partial Piezoelectric Layers

“…which can be expanded for each piezoelectric layer as (9) in which (1) p A and (2) p A denote the area of the cross section of the top and bottom piezoelectric layers, respectively.…”

“…Among them, piezoelectric materials [9][10][11][12] are in many engineering systems and are used for different applications involving sensing and actuation ranging from macro systems to microsystems. For instance, they are utilized for active vibration control, precise position adjustment and control, different types of energy harvesting, and static and dynamic actuations.…”

Thermal and Mechanical Analyses of Compliant Thermoelectric Coils for Flexible and Bio-Integrated Devices

“…A collection of recent works [23][24][25][26][27][28][29][30][31][32] exploit a new strategy, i.e., buckling-guided 3D assembly that forms the 3D mesostructures by the compressive buckling of 2D precursors selectively bonded onto prestretched elastomer substrates. This assembly technique is intrinsically compatible with the planar technologies for a wide range of classes of functional materials, including device-grade semiconductors, and has some attractive features such as parallel operation, high speed, and size scalability, ranging from nanometers to centimeters [33][34][35][36][37][38][39][40]. These capabilities provide more design spaces for this assembly technique, and demonstrate a promising future for practical applications.…”