Dr. Paul W. Alexander Profile

Dr. Paul W. Alexander

Senior Researcher at General Motors Corp

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Author

Publications (10)

Proceedings Article | 28 April 2023 Presentation

Antagonistic actuation of hinged tile-based curling air surface for advanced functionalities

Tiantian Li, Jonathan Luntz, Diann Brei, Paul Alexander, Wonhee Kim

Proceedings Volume PC12483, PC124830F (2023) https://doi.org/10.1117/12.2666236

KEYWORDS: Bladder, Design and modelling, Control systems, Vacuum, Model-based design, Integration, Bistability

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Proceedings Article | 16 April 2014 Paper

Damper-controlled switch for SMA motion smoothing

Clover Aguayo, Brent Utter, Jonathan Luntz, Richard Gonzalez, Diann Brei, Nancy Johnson, Paul Alexander

Proceedings Volume 9059, 90590H (2014) https://doi.org/10.1117/12.2052871

KEYWORDS: Shape memory alloys, Actuators, Switches, Switching, Prototyping, Control systems, Power supplies, Data acquisition, Computer programming, Standards development

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While the use of SMA-actuated devices continues to grow in many industries, current device limitations pose a challenge to successful adoption for certain classes of applications. SMA-actuated devices typically demonstrate motion with non-constant velocity due to the non-linear thermo-mechanically coupled behavior of SMA material transformation, and motion sensitivity to external factors such as voltage and load. This variation in motion can lead to the perception of poor device quality, limiting SMA-actuated devices to applications hidden from the sight of the product user, or requiring them to be augmented with higher cost controls to improve the motion quality. Therefore, a need exists for simple, passive, low-cost device technologies that enable the designer to prescribe desired motion characteristics with relative insensitivity to fluctuation in operating conditions. This paper presents a Damper Controlled Switch (DCS) mechanism that delivers constant velocity and relative insensitivity to operating conditions when combined with a standard SMA wire actuator. The DCS includes a damper that acts against a spring to open a switch when the velocity exceeds a tunable threshold. To validate the ability of the DCS to provide the desired motion quality, experiments were conducted comparing the normal motion of the SMA actuator to the motion produced when the same actuator was fitted with a DCS prototype. The addition of the DCS produced nearly constant actuator velocity, performing significantly better than the SMA actuator alone. The tunability of the DCS was demonstrated producing a wide range of attainable constant velocities. Finally, a set of experiments explored the DCS’s sensitivity to voltage and load, indicating a low sensitivity to a wide range of operating parameters for which the operating limits were identified. The DCS represents a simple, compact technology based on passive, low-cost components, providing a very practical solution that will enable integration of SMA-actuated devices into a broader class of applications.

Proceedings Article | 30 March 2012 Paper

Lightweight thermal energy recovery system based on shape memory alloys: a DOE ARPA-E initiative

Alan Browne, Andrew Keefe, Paul Alexander, Nilesh Mankame, Patrick Usoro, Nancy Johnson, Jan Aase, Peter Sarosi, Geoffrey McKnight, Guillermo Herrera, Christopher Churchill, John Shaw, Jeff Brown

Proceedings Volume 8343, 834306 (2012) https://doi.org/10.1117/12.913275

KEYWORDS: Shape memory alloys, Thermoelectric materials, Thermal efficiency, Energy efficiency, Prototyping, Combustion, Liquids, Neodymium, Thermodynamics, Standards development

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Proceedings Article | 1 April 2009 Paper

SMA wire actuator modular design framework

Jonathan Luntz, Brian Barnes, Diann Brei, Paul Alexander, Alan Browne, Nancy Johnson

Proceedings Volume 7290, 729008 (2009) https://doi.org/10.1117/12.816752

KEYWORDS: Shape memory alloys, Actuators, Computer architecture, Interfaces, Systems modeling, Human-machine interfaces, Optimization (mathematics), Data modeling, Manufacturing, Performance modeling

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Proceedings Article | 20 March 2008 Paper

Stabilizing shape memory alloy actuator performance through cyclic shakedown: an empirical study

Helen Sun, Anupam Pathak, Jonathan Luntz, Diann Brei, Paul Alexander, Nancy Johnson

Proceedings Volume 6930, 69300Q (2008) https://doi.org/10.1117/12.775998

KEYWORDS: Shape memory alloys, Actuators, Smart structures, Manufacturing, Thermal modeling, Performance modeling

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Proceedings Article | 11 April 2007 Paper

General Motors and the University of Michigan smart materials and structures collaborative research laboratory

Diann Brei, Jonathan Luntz, John Shaw, Nancy Johnson, Alan Browne, Paul Alexander, Nilesh Mankame

Proceedings Volume 6527, 65270U (2007) https://doi.org/10.1117/12.715334

KEYWORDS: Smart materials, Shape memory alloys, Basic research, Analytical research, Packaging, Aerospace engineering, Control systems, Instrument modeling, Actuators

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Proceedings Article | 5 April 2006 Paper

The fabrication and deformation capabilities of two dimensionally graded DEPP FGP

Paul Alexander, Diann Brei, John Halloran

Proceedings Volume 6173, 617301 (2006) https://doi.org/10.1117/12.658638

KEYWORDS: Actuators, Performance modeling, Fabrication, Ferroelectric materials, Dielectrics, Microfabrication, Motion models, Ceramics, Matrices, Prototyping

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Proceedings Article | 17 May 2005 Paper

The fabrication and material characterization of PZT based functionally graded piezoceramics

Paul Alexander, Diann Brei, John Halloran

Proceedings Volume 5764, (2005) https://doi.org/10.1117/12.599749

KEYWORDS: Ferroelectric materials, Actuators, Ceramics, Surface finishing, Dielectrics, Fabrication, Material characterization, Microfabrication, Polishing, Reliability

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Proceedings Article | 16 August 2001 Paper

Experimental characterization and model validation of the quasi-static performance of piezoceramic telescopic actuators

Paul Alexander, Diann Brei

Proceedings Volume 4327, (2001) https://doi.org/10.1117/12.436546

KEYWORDS: Actuators, Prototyping, 3D modeling, Polymers, Performance modeling, Polymeric actuators, Error analysis, Electrodes, Polymerization, Ferroelectric materials

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Proceedings Article | 22 June 2000 Paper

Fabrication and experimental characterization of d31 telescopic piezoelectric actuators

Paul Alexander, Diann Brei, Weiguo Miao, John Halloran, Richard Gentilman, Gerald Schmidt, Patrick McGuire, John Hollenbeck

Proceedings Volume 3985, (2000) https://doi.org/10.1117/12.388825

KEYWORDS: Actuators, Prototyping, Fabrication, Ceramics, Ferroelectric materials, Polymers, Polymerization, Aluminum, Polymeric actuators, Solids

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Showing 5 of 10 publications

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