Dr. Stephen M. Leadenham Profile

Dr. Stephen M. Leadenham

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Author

Publications (11)

Proceedings Article | 11 April 2017 Paper

Metamaterial piezoelectric beam with synthetic impedance shunts

Christopher Sugino, Stephen Leadenham, Massimo Ruzzene, Alper Erturk

Proceedings Volume 10164, 1016410 (2017) https://doi.org/10.1117/12.2260320

KEYWORDS: Electrodes, Metamaterials, Systems modeling, Signal attenuation, Electromechanical design, Capacitance, Wet etching, Etching, Nickel, Lead, Digital signal processing, Device simulation, Crystals, Simulink, Analog electronics, Resistors, Resistance

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Proceedings Article | 15 April 2016 Paper

Power conditioning for low-voltage piezoelectric stack energy harvesters

E. Skow, S. Leadenham, K. Cunefare, A. Erturk

Proceedings Volume 9799, 97990P (2016) https://doi.org/10.1117/12.2219211

KEYWORDS: Energy harvesting, Sensor networks, Acoustics, Device simulation, Diodes, Inductance, Capacitors, Bridges, Resistance, Capacitance

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Proceedings Article | 15 April 2016 Paper

Figure of merit comparison of PP-based electret and PVDF-based piezoelectric polymer energy harvesters

M. Mrlík, S. Leadenham, M. AlMaadeed, A. Erturk

Proceedings Volume 9799, 979923 (2016) https://doi.org/10.1117/12.2222283

KEYWORDS: Energy harvesting, Ferroelectric polymers, Polymers, Ceramics, Ferroelectric materials, Piezoelectric effects, Calcium, Capacitance, Resistance, Electrodes

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Proceedings Article | 15 April 2016 Paper

Dramatic effect of fluid damping on the performance of a nonlinear M-shaped broadband energy harvester

Christopher Sugino, David Tan, Stephen Leadenham, Alper Erturk

Proceedings Volume 9799, 979913 (2016) https://doi.org/10.1117/12.2219400

KEYWORDS: Energy harvesting, Mathematical modeling, Nonlinear dynamics, Resonance enhancement, Oscillators, Complex systems, Systems modeling, Data modeling, Solids, Mechanical engineering

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Proceedings Article | 15 April 2016 Paper

Exploiting material softening in hard PZTs for resonant bandwidth enhancement

S. Leadenham, A. Moura, A. Erturk

Proceedings Volume 9799, 97992F (2016) https://doi.org/10.1117/12.2219370

KEYWORDS: Ferroelectric materials, Energy harvesting, Resistors, Resistance, Ceramics, Feedback control, Mechanical engineering, Resonance enhancement, Smart structures, Complex systems

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Proceedings Article | 2 April 2015 Paper

Modeling and identification of nonlinear electroelastic and dissipative parameters for PZT-5A and PZT-5H bimorphs: a dynamical systems approach

Stephen Leadenham, Brian Ferri, Alper Erturk

Proceedings Volume 9431, 94311I (2015) https://doi.org/10.1117/12.2084455

KEYWORDS: Data modeling, Electrodes, Ferroelectric materials, Energy harvesting, Resistance, Systems modeling, Dynamical systems, Vibration control, Electroluminescent displays, Data acquisition

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Proceedings Article | 2 April 2015 Paper

Broadband performance of a patterned piezoelectric energy harvester integrated with a continuous elastoacoustic mirror

Matteo Carrara, Jason Kulpe, Stephen Leadenham, Michael Leamy, Alper Erturk

Proceedings Volume 9431, 943102 (2015) https://doi.org/10.1117/12.2084319

KEYWORDS: Mirrors, Resistance, Electrodes, Wave propagation, Energy harvesting, Wave plates, Optical lithography, Ferroelectric materials, Capacitance, Ferroelectric polymers

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Proceedings Article | 1 April 2014 Paper

Ultrasound acoustic wave energy transfer and harvesting

Shima Shahab, Stephen Leadenham, François Guillot, Karim Sabra, Alper Erturk

Proceedings Volume 9057, 90570F (2014) https://doi.org/10.1117/12.2045198

KEYWORDS: Receivers, Acoustics, Resistance, Energy transfer, Ultrasonography, Finite element methods, Ultrasonics, Spherical lenses, Transmitters, Energy harvesting

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Proceedings Article | 1 April 2014 Paper

Nonlinear modeling, strength-based design, and testing of flexible piezoelectric energy harvesters under large dynamic loads for rotorcraft applications

Stephen Leadenham, Alper Erturk

Proceedings Volume 9057, 90571W (2014) https://doi.org/10.1117/12.2045167

KEYWORDS: Resistance, Resistors, Energy harvesting, Electrodes, Electromechanical design, Reliability, Failure analysis, Mathematical modeling, Motion models, Shape analysis

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There has been growing interest in enabling wireless health and usage monitoring for rotorcraft applications, such as helicopter rotor systems. Large dynamic loads and acceleration fluctuations available in these environments make the implementation of vibration-based piezoelectric energy harvesters a very promising choice. However, such extreme loads transmitted to the harvester can also be detrimental to piezoelectric laminates and overall system reliability. Particularly flexible resonant cantilever configurations tuned to match the dominant excitation frequency can be subject to very large deformations and failure of brittle piezoelectric laminates due to excessive bending stresses at the root of the harvester. Design of resonant piezoelectric energy harvesters for use in these environments require nonlinear electroelastic dynamic modeling and strength-based analysis to maximize the power output while ensuring that the harvester is still functional. This paper presents a mathematical framework to design and analyze the dynamics of nonlinear flexible piezoelectric energy harvesters under large base acceleration levels. A strength-based limit is imposed to design the piezoelectric energy harvester with a proof mass while accounting for material, geometric, and dissipative nonlinearities, with a focus on two demonstrative case studies having the same linear fundamental resonance frequency but different overhang length and proof mass values. Experiments are conducted at different excitation levels for validation of the nonlinear design approach proposed in this work. The case studies in this work reveal that harvesters exhibiting similar behavior and power generation performance at low excitation levels (e.g. less than 0.1g) can have totally different strength-imposed performance limitations under high excitations (e.g. above 1g). Nonlinear modeling and strength-based design is necessary for such excitation levels especially when using resonant cantilevers with no geometric constraint.

Proceedings Article | 1 April 2014 Paper

Global nonlinear electroelastic dynamics of a bimorph piezoelectric cantilever for energy harvesting, sensing, and actuation

Stephen Leadenham, Alper Erturk

Proceedings Volume 9057, 905702 (2014) https://doi.org/10.1117/12.2045161

KEYWORDS: Energy harvesting, Electroluminescent displays, Data modeling, Resistance, Mechanical sensors, Mathematical modeling, Solids, Electrodes, Sensing systems, Vibration control

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Inherent nonlinearities of piezoelectric materials are inevitably pronounced in various engineering applications such as sensing, actuation, their combined applications for vibration control, and most recently, energy harvesting from dynamical systems. The existing literature focusing on the dynamics of electroelastic structures made of piezoelectric materials have explored such nonlinearities in a disconnected way for the separate problems of mechanical and electrical excitation such that nonlinear resonance trends have been assumed to be due to different additional terms in constitutive equations by different researchers. Similar manifestations of softening nonlinearities have been attributed to purely elastic nonlinear terms, coupling nonlinearities, hysteresis, or a combination of these effects, by various authors. However, a reliable nonlinear constitutive equation for a given piezoelectric material is expected to be rather unique and valid regardless of the application, e.g. energy harvesting, sensing, or actuation. A systematic approach focusing on the two-way coupling can result in a sound mathematical framework. To this end, the present work investigates the nonlinear dynamic behavior of a bimorph piezoelectric cantilever under low-to-high mechanical and electrical excitation levels in energy harvesting, sensing, and actuation. A physical model is proposed including both ferroelastic hysteresis, stiffness, and electromechanical coupling nonlinearities. A lumped parameter electroelastic model is developed by accounting for these nonlinearities to analyze the primary resonance of a cantilever using the method of harmonic balance. Strong agreement between the model and experimental investigation is found, providing solid evidence that the the dominant source of observed softening nonlinear effects in geometrically linear piezolectric cantilever beams is well represented by a quadratic term resulting from ferroelastic hysteresis. Electromechanical coupling and cubic softening nonlinearities are observed to become effective only near the physical limits of the brittle and stiff bimorph cantilever used in the experiments, revealing that the quadratic nonlinearity associated with hysteresis has the primary role in nonlinear nonconservative dynamic behavior.

Proceedings Article | 9 March 2014 Paper

Optimal piezoelectric energy harvesting using elastoacoustic mirrors by frequency-wavenumber domain investigation

Matteo Carrara, Jason Kulpe, Stephen Leadenham, Michael Leamy, Alper Erturk

Proceedings Volume 9057, 905705 (2014) https://doi.org/10.1117/12.2044960

KEYWORDS: Mirrors, Wave propagation, Energy harvesting, Electrodes, Satellites, Resistance, Capacitance, Optical lithography, Fourier transforms, Wave plates

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Showing 5 of 11 publications

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