Inkjet printing P(VDF-TrFE-CTFE) actuators for large bending strains

Additive manufacturing of sensors and actuators together with structural materials and electronics will make it possible to fabricate innovative system designs that are overly laborious to realise with conventional methods. While printing of the structural materials and electronics are advancing fast, the additive manufacturing methods for...

Exploring the BiFeO3-PbTiO3-SrTiO3 Ternary System to Obtain Good Piezoelectrical Properties at Low and High Temperatures

In this work, we investigated the piezoelectric properties of BiFeO3-rich (1 − (y + x)) BiFeO3–y PbTiO3–x SrTiO3 (0.1 ≤ x ≤ 0.35; 0.1 ≤ y ≤ 0.3) bulk piezoceramics, as this system could potentially lead to the development of bulk piezoelectric ceramics that are suitable for high-temperature applications (>200 °C). Samples with various levels...

An Ultrasonically-Powered System for 1.06mm³ Implantable Optogenetics and Drug Delivery Dust

This brief presents an ultrasonically powered micro-system for deep tissue optogenetic stimulation. The developed system is composed of a Base for Powering and Controlling (BPC) and an implantable Dust for optogenetics and drug delivery. The Dust consists of a piezoelectric crystal, a rectifier chip, and a micro-scale custom-designed light...

Ultrasonically Powered and Controlled Microsystem for Dual-Wavelength Optogenetics with a Multi-Load Regulation Scheme

This letter presents an ultrasonically powered dual-wavelength optogenetic device that targets simultaneous excitation and inhibition of neural activities, or in a broader sense, optical stimulation in two distinct wavelengths for targeting different populations of neurons. This can be applied to a variety of neurological disorders. The...

Applied and fundamental studies of vibrating 2D membranes

This thesis encompasses both applied and fundamental studies of suspended van der Waals materials. Chapters 1 and 2 give an introduction to the field of 2D materials and some of the critical methods which facilitate the study of the suspended structures. In Chapters 3 and 4 we focus on the applications of graphene in barometric pressure sensors...

Proportional Microvalve Using a Unimorph Piezoelectric Microactuator

Microvalves are important flow-control devices in many standalone and integrated microfluidic applications. Polydimethylsiloxane (PDMS)-based pneumatic microvalves are commonly used but they generally require large peripheral connections that decrease portability. There are many alternatives found in the literature that use Si-based microvalves,...

Proportional Microvalve Using A Piezoelectric Unimorph Microactuator

Microvalves are important flow-control components in many standalone and integrated microfluidic circuits. Although there is a large body of work regarding<br/>microvalves, there is still a need for an easyto-fabricate, small-footprint, low-power device that can control both liquids and gases at moderate pressures. This paper details the...

Understanding piezoelectric composite–based actuators with nonlinear and 90 domain walls effects

Piezoelectric materials possess nonlinear behavior when actuated in a large electric field and show a large deflection when embedded inside a composite laminate such as a LIghtweight Piezoelectric Composite Actuator. Linear and nonlinear COMSOL multi-physics finite element models were developed and validated using the actuation response of three...

Piezoelectric and mechanical properties of structured PZT–epoxy composites

Structured lead zirconium titanate (PZT)–epoxy composites are prepared by dielectrophoresis. The piezoelectric and dielectric properties of the composites as a function of PZT volume fraction are investigated and compared with the corresponding unstructured composites. The effect of poling voltage on piezoelectric properties of the composites is...

Post-buckled precompressed (PBP) subsonic micro flight control actuators and surfaces

This paper describes a new class of flight control actuators using Post-Buckled Precompressed (PBP) piezoelectric elements to provide much improved actuator performance. These PBP actuator elements are modeled using basic large deflection Euler-beam estimations accounting for laminated plate effects. The deflection estimations are then coupled...

Post-Buckled Precompressed (PBP) piezoelectric actuators for UAV flight control

This paper presents the use of a new class of flight control actuators employing Post-Buckled Precompressed (PBP) piezoelectric elements in morphing wing Uninhabited Aerial Vehicles (UAVs). The new actuator relieson axial compression to amplify deflections and control forces simultaneously. Two designs employing morphingwing panels based on PBP...

Post-buckled precompressed (PBP) elements: A new class of flight control actuators enhancing high-speed autonomous VTOL MAVs

This paper describes a new class of flight control actuators using Post-Buckled Precompressed (PBP) piezoelectric elements. These actuators are designed to produce significantly higher deflection and force levels than conventional piezoelectric actuator elements. Classical laminate plate theory (CLPT) models are shown to work very well in...

Airfoil drag elimination and stall suppression via piezoelectric dynamic tangential synthetic jet actuators

This paper describes a new method for drag elimination and stall suppression via tangential synthetic jet actuators. This boundary layer control (BLC) method is shown to perform as well as continuous and normal synthetic jet BLC methods but without fouling difficulties, system-level complexity or extreme sensitivity to Reynolds number. Classical...

Adaptive aerostructures: The first decade of flight on uninhabited aerial vehicles

Although many subscale aircraft regularly fly with adaptive materials in sensors and small components in secondary subsystems, only a handful have flown with adaptive aerostructures as flight critical, enabling components. This paper reviews several families of adaptive aerostructures which have enabled or significantly enhanced flightworthy...

Design and testing of piezoelectric flight control actuators for hard-launch munitions

A new technique is presented for designing actuators for guided hard-launch adaptive munitions by using actuator and substrate strain limits, static analysis methods and matching the local actuator strains along its length by varying the width. This Load-Matched design technique leads to an exponential area distribution as a function of length...