Underwater Dynamic Actuation of Macro-Fiber Composite Flaps With Different Aspect Ratios: Electrohydroelastic Modeling, Testing, and Characterization

2014 ◽  
Author(s):  
Shima Shahab ◽  
Alper Erturk
Keyword(s):  
Electromechanical Coupling ◽  
Fiber Composite ◽  
Actuation Voltage ◽  
Metal Composite ◽  
Actuation Frequency ◽  
Aspect Ratios ◽  
Current Consumption ◽  
Macro Fiber Composite ◽  
Tip Velocity ◽  
Hydrodynamic Function

Macro-fiber composite (MFC) actuators offer simple and scalable design, robustness, noiseless performance, strong electromechanical coupling, and particularly a balance between the actuation force and deformation capabilities, which is essential to effective and agile biomimetic locomotion. Recent efforts in our lab have shown that MFC bimorphs with polyester electrode sheets can successfully be employed for fish-like aquatic locomotion in both tethered and untethered operation. MFC swimmers can outperform other smart material-based counterparts, such as the compliant ionic polymer-metal composite based swimmers, in terms of swimming speed per body length. Cantilevered flaps made of MFC bimorphs with different aspect ratios can be employed for underwater actuation, sensing, and power generation, among other aquatic applications of direct and converse piezoelectric effects. In an effort to develop linearized electrohydroelastic models for such cantilevers, the present work investigates MFC bimorphs with three different aspect ratios. The MFCs used in this study use the 33-mode of piezoelectricity with interdigitated electrodes. Underwater dynamic actuation frequency response functions (FRFs) of the MFCs are defined as the tip velocity per actuation voltage (tip velocity FRF) and current consumption per actuation voltage (admittance FRF). The tip velocity and admittance FRFs are modeled analytically for in-air actuation and validated experimentally for all aspect ratios. Underwater tip velocity and admittance FRFs are then derived by combining their in-air counterparts with corrected hydrodynamic functions. The corrected hydrodynamic functions are also identified from aluminum cantilevers of similar aspect ratios. Both tip vibration and current consumption per voltage input are explored. The failure of Sader’s hydrodynamic function for low length-to-width aspect ratios is shown. Very good correlation is observed between model simulations and experimental measurements using aspect ratio-dependent, corrected hydrodynamic function.

Analytical and Experimental Characterization of Macro-Fiber Composite Actuated Thin Clamped-Free Unimorph Benders

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Onur Bilgen ◽  
Alper Erturk ◽  
Daniel J. Inman
Keyword(s):  
Fiber Composite ◽  
Steel Substrate ◽  
Actuation Voltage ◽  
Structural Response ◽  
Distributed Parameter ◽  
Experimental Characterization ◽  
Macro Fiber Composite ◽  
Cantilevered Beams ◽  
Tip Velocity

A type of piezoceramic composite actuator known as Macro-Fiber Composite (MFC) is used commonly for actuation in smart-material structures. In this paper, a linear distributed parameter electromechanical model is proposed to predict the structural response to MFC actuated clamped-free thin cantilevered beams. The structural frequency response behavior between the tip velocity of the cantilever beam and the actuation voltage of the piezoelectric material is investigated experimentally for cantilevered unimorph MFC actuated benders with aluminum, brass, and steel substrate materials with different thicknesses. Good correlation is observed between the model and the experimental observations.

scholarly journals Coupling of experimentally validated electroelastic dynamics and mixing rules formulation for macro-fiber composite piezoelectric structures

2016 ◽  
Vol 28 (12) ◽  
pp. 1575-1588 ◽  
Author(s):  
Shima Shahab ◽  
Alper Erturk
Keyword(s):  
Power Generation ◽  
Composite Structures ◽  
Electromechanical Coupling ◽  
Fiber Composite ◽  
Rectangular Cross Section ◽  
Mixing Rules ◽  
Modeling Framework ◽  
Interdigitated Electrodes ◽  
Macro Fiber Composite ◽  
Piezoelectric Structures

Piezoelectric structures have been used in a variety of applications ranging from vibration control and sensing to morphing and energy harvesting. In order to employ the effective 33-mode of piezoelectricity, interdigitated electrodes have been used in the design of macro-fiber composites which employ piezoelectric fibers with rectangular cross section. In this article, we present an investigation of the two-way electroelastic coupling (in the sense of direct and converse piezoelectric effects) in bimorph cantilevers that employ interdigitated electrodes for 33-mode operation. A distributed-parameter electroelastic modeling framework is developed for the elastodynamic scenarios of piezoelectric power generation and dynamic actuation. Mixing rules (i.e. rule of mixtures) formulation is employed to evaluate the equivalent and homogenized properties of macro-fiber composite structures. The electroelastic and dielectric properties of a representative volume element (piezoelectric fiber and epoxy matrix) between two neighboring interdigitated electrodes are then coupled with the global electro-elastodynamics based on the Euler–Bernoulli kinematics accounting for two-way electromechanical coupling. Various macro-fiber composite bimorph cantilevers with different widths are tested for resonant dynamic actuation and power generation with resistive shunt damping. Excellent agreement is reported between the measured electroelastic frequency response and predictions of the analytical framework that bridges the continuum electro-elastodynamics and mixing rules formulation.

Fish-Like Self Propulsion Using Flexible Piezoelectric Composites

2012 ◽  
Author(s):  
Lejun Cen ◽  
Alper Erturk
Keyword(s):  
Smart Materials ◽  
Electromechanical Coupling ◽  
High Efficiency ◽  
Fiber Composite ◽  
Actuation Voltage ◽  
Robotic Fish ◽  
Circuit Board ◽  
Modeling Framework ◽  
Actuator Dynamics ◽  
Body Theory

The capacity of humankind to mimic fish-like locomotion for engineering applications depends mainly on the availability of suitable actuators. Researchers have recently focused on developing robotic fish using smart materials, particularly Ionic Polymer-Metal Composites (IPMCs), as a compliant, noise-free, and scalable alternative to conventional motor-based propulsion systems. In this paper, we investigate fish-like self propulsion using flexible bimorphs made of Macro-Fiber Composite (MFC) piezoelectric laminates. Similar to IPMCs, MFCs also exhibit high efficiency in size, energy consumption, and noise reduction. In addition, MFCs offer large dynamic forces in bending actuation, strong electromechanical coupling as well as both low-frequency and high-frequency performance capabilities. The experimental component of the presented work focuses on the characterization of an MFC bimorph propulsor for thrust generation in a quiescent fluid as well as the development of a preliminary robotic fish prototype incorporating a microcontroller and a printed-circuit-board (PCB) amplifier to generate high actuation voltage for battery-powered free locomotion. From the theoretical standpoint, a reliable modeling framework that couples the actuator dynamics, hydroelasticity, and fish locomotion theory is essential to both design and control of robotic fish. Therefore, a distributed-parameter electroelastic model with fluid effects and actuator dynamics is coupled with the elongated body theory. Both in-air and underwater experiments are performed to verify the incorporation of hydrodynamic effects in the linear actuation regime. For electroelastically nonlinear actuation levels, experimentally obtained underwater vibration response is coupled with the elongated body theory to predict the thrust output. Experiments are conducted to validate the electrohydroelastic modeling approach employed in this work and to characterize the performance of an MFC bimorph propulsor. Finally, a battery-powered preliminary robotic fish prototype is developed and tested in free locomotion.

Hydrodynamic Thrust Generation and Power Consumption Investigations for Piezoelectric Fins With Different Aspect Ratios

2015 ◽  
Author(s):  
Shima Shahab ◽  
David Tan ◽  
Alper Erturk
Keyword(s):  
Aspect Ratio ◽  
Power Consumption ◽  
Fiber Composite ◽  
Swimming Performance ◽  
Actuation Voltage ◽  
Structural Deformation ◽  
Thrust Coefficient ◽  
Drag Coefficients ◽  
Aspect Ratios ◽  
Thrust Generation

Bio-inspired hydrodynamic thrust generation using piezoelectric transduction has recently been explored using Macro-Fiber Composite (MFC) actuators. The MFC technology strikes a balance between the actuation force and structural deformation levels for effective swimming performance, and additionally offers geometric scalability, silent operation, and ease of fabrication. Recently we have shown that mean thrust levels comparable to biological fish of similar size can be achieved using MFC fins. The present work investigates the effect of length-to-width (L/b) aspect ratio on the hydrodynamic thrust generation performance of MFC cantilever fins by accounting for the power consumption level. It is known that the hydrodynamic inertia and drag coefficients are controlled by the aspect ratio especially for L/b<5. The three MFC bimorph fins explored in this work have the aspect ratios of 2.1, 3.9, and 5.4. A nonlinear electrohydroelastic model is employed to extract the inertia and drag coefficients from the vibration response to harmonic actuation for the first bending mode. Experiments are then conducted for various actuation voltage levels to quantify the mean thrust resultant and power consumption levels for different aspect ratios. Variation of the thrust coefficient of the MFC fins with aspect ratio is also modeled and validated.

Macro-Fiber Composite Actuators for Flow Control of a Variable Camber Airfoil

2010 ◽  
Vol 22 (1) ◽  
pp. 81-91 ◽  
Author(s):  
Onur Bilgen ◽  
Carlos De Marqui ◽  
Kevin B. Kochersberger ◽  
Daniel J. Inman
Keyword(s):  
Flow Control ◽  
Fiber Composite ◽  
Macro Fiber Composite

Analysis of Wrinkled Membranes Bounded With Macro-Fiber Composite (MFC) Actuators

2010 ◽  
Author(s):  
Alireza Doosthoseini ◽  
Armaghan Salehian ◽  
Matthew Daly
Keyword(s):  
Finite Element ◽  
Fiber Composite ◽  
The Other ◽  
Horizontal Direction ◽  
Finite Element Code ◽  
Rectangular Shape ◽  
Macro Fiber Composite

In this paper we focus on a study which involves quantifying the effects of Macro Fiber Composite (MFC) actuators on the pattern and magnitude of wrinkles in a membrane when exposed to various loadings. An ABAQUS finite element code is employed for this research. The membrane in this study has a rectangular shape which is clamped at one edge and is free to move in the horizontal direction at the other edge. MFC actuators are bounded to the membrane to make a bimorph configuration.

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