Dr. Steven F. Griffin Profile

Dr. Steven F. Griffin

MSSS Chief Engineer

SPIE Involvement:

Author | Editor

Publications (20)

Proceedings Article | 18 April 2022 Presentation

Smart structures in giant lasers, musical instruments, and other applications

Steven Griffin

Proceedings Volume PC12046, PC1204601 (2022) https://doi.org/10.1117/12.2622242

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Proceedings Article | 4 April 2017 Paper

Self-tuning tuned mass damper (TMD)

Steven Griffin

Proceedings Volume 10166, 101660C (2017) https://doi.org/10.1117/12.2263563

KEYWORDS: Resonators, Aerospace engineering, Actuators, Resistors, Finite element methods, Directed self assembly, Resistance, Mathematical modeling, Analytical research, Smart structures

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Proceedings Article | 4 April 2017 Presentation + Paper

Bimorph-driven synthetic jet actuators optimized for various piezoelectric materials using a low-order model

Tianliang Yu, George Lesieutre, Steven Griffin, Daniel Brzozowski, Aaron Sassoon

Proceedings Volume 10166, 101660B (2017) https://doi.org/10.1117/12.2263359

KEYWORDS: Actuators, Optimization (mathematics), Performance modeling, Systems modeling, Device simulation, Smart materials, Quantum efficiency, Crystals, Instrument modeling, Ferroelectric polymers, Motion models

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Synthetic jet actuators are of interest for potential applications to active flow control and thermal management. Resonant piezoelectric-diaphragm-type configurations are commonly considered. Modeling of such actuators remains a challenge due to complexities associated with both electro-elastic and fluid-structure coupling, as well as potential non-linearities in both. A key metric for synthetic jet performance is the time-averaged jet momentum. Linear lumped-element modeling is an approach that has demonstrated the ability to predict jet momentum in terms of input frequency and voltage; however, it neglects nonlinearity and increasing losses at high amplitude. Full electro-elastic-fluidic finite element modeling makes the most accurate prediction but is computationally expensive for design and optimization purposes. The assumed-modes method provides an energy-based low-order model which captures electro-elastic and acoustic-structure couplings with adequate accuracy. Tri-laminar circular plates under clamped boundary conditions were modeled using the assumed-modes method. Maximization of jet momentum is considered via the maximization of surrogate device metrics: free volume displacement, effective blocking pressure, strain energy, and device coupling coefficient. The driving frequency of the actuator is treated as a constraint in the optimization which nominally matches the fundamental acoustic natural frequency of the cylindrical cavity. Device configurations were obtained for various polycrystalline and single crystal piezoelectric materials, driven at 10% of their coercive fields in the model. The optimal configurations approximate a simply-supported circular plate with complete piezo coverage. The relative merits of individual materials were also discerned from the optimization results. The low mechanical loss factor of PZT8 enables high output at resonance, while high loss factor and low stiffness limit the utility of PVDF in this application. Due to a combination of lower loss factor and higher coupling, single crystal materials modestly outperform PZT5A.

Proceedings Article | 22 July 2014 Paper

Design of the planets telescope structure

Steven Griffin, Matthew Edwards, Jeff Kuhn

Proceedings Volume 9145, 91455D (2014) https://doi.org/10.1117/12.2057313

KEYWORDS: Telescopes, Space telescopes, Optical instrument design, Planets, Mirrors, Carbon, Finite element methods, Wind measurement, Integrated modeling, Off axis mirrors

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Proceedings Article | 10 March 2014 Paper

Displacement amplified synthetic jets

Steve Griffin, Shawn Haar, Edward Whalen

Proceedings Volume 9059, 905903 (2014) https://doi.org/10.1117/12.2046442

KEYWORDS: Actuators, Control systems

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Proceedings Article | 13 September 2012 Paper

Vibration damping for the Segmented Mirror Telescope

Joseph Maly, Adam Yingling, Steven Griffin, Brij Agrawal, Richard Cobb, Trevor Chambers

Proceedings Volume 8450, 845004 (2012) https://doi.org/10.1117/12.926567

KEYWORDS: Image segmentation, Mirrors, Telescopes, Segmented mirrors, Space telescopes, Magnetism, James Webb Space Telescope, Silicon carbide, Actuators, Acoustics

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Proceedings Article | 4 May 2009 Paper

State space representation of optical systems

Clay Jones, Steve Griffin

Proceedings Volume 7338, 73380J (2009) https://doi.org/10.1117/12.814981

KEYWORDS: Mirrors, Systems modeling, Motion models, Space mirrors, Control systems, Optical components, Sensors, Finite element methods, Performance modeling, Matrices

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Proceedings Article | 29 July 2004 Paper

The vibro-acoustic launch protection experiment overview and flight results summary

Charlotte Gerhart, B. Kyle Henderson, Steve Griffin, Anthony Lazzaro, Michael Evert, Warren McCrary, Emil Ardelean

Proceedings Volume 5388, (2004) https://doi.org/10.1117/12.547377

KEYWORDS: Acoustics, Rockets, Vibration isolation, Signal attenuation, Complex systems, Space operations, Satellites, Skin, Composites, Active isolation

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Proceedings Article | 18 December 2002 Paper

Development of a sparse-aperture testbed for optomechanical control of space-deployable structures

Karl Schrader, Rob Fetner, Steven Griffin, Richard Erwin

Proceedings Volume 4849, (2002) https://doi.org/10.1117/12.460569

KEYWORDS: Mirrors, Image segmentation, Calibration, Metrology, Space telescopes, Control systems, Composites, Tolerancing, Imaging systems, Analytical research

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Proceedings Article | 28 July 2000 Paper

Experimental control of microdynamic events observed during the testing of a large deployable optical structure

Ruth Moser, R. Scott Erwin, Karl Schrader, Kevin Bell, Steven Griffin, Michael Powers

Proceedings Volume 4013, (2000) https://doi.org/10.1117/12.394007

KEYWORDS: Interferometers, Ferroelectric materials, Mirrors, Control systems, Space telescopes, Acoustics, Sensors, Device simulation, Objectives, Analytical research

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Proceedings Article | 9 July 1999 Paper

Hybrid launch isolation system

Dino Sciulli, Steven Griffin

Proceedings Volume 3674, (1999) https://doi.org/10.1117/12.351572

KEYWORDS: Optical isolators, Satellites, Actuators, Space operations, Signal attenuation, Passive isolation, Active isolation, Titanium, Control systems, Sensors

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Proceedings Article | 8 December 1998 Paper

Current status of the UltraLITE control technology testbed for optical mirror mass control

Lawrence Robertson, Steven Griffin, Michael Powers, Richard Cobb

Proceedings Volume 3430, (1998) https://doi.org/10.1117/12.332477

KEYWORDS: Mirrors, Sensors, Control systems, Actuators, Control systems design, Device simulation, Electronic test equipment, Data modeling, Ferroelectric materials, Space operations

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Proceedings Article | 8 December 1998 Paper

Ultralightweight structures for deployed optics

Steven Griffin, Lawrence Robertson, Steven Huybrechts

Proceedings Volume 3430, (1998) https://doi.org/10.1117/12.332488

KEYWORDS: Actuators, Composites, Mirrors, Ferroelectric materials, Interfaces, Active optics, Feedback loops, Sensors, Analytical research, Acoustics

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Proceedings Article | 28 August 1998 Paper

Air force research laboratory's technology programs addressing deployable space optical systems

Kevin Bell, Michael Powers, Steven Griffin, Steven Huybrechts

Proceedings Volume 3356, (1998) https://doi.org/10.1117/12.324475

KEYWORDS: Mirrors, Space telescopes, Actuators, Control systems, Imaging systems, Composites, Telescopes, Space mirrors, Adaptive optics, Sensors

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Proceedings Article | 27 July 1998 Paper

Hybrid structural/acoustic control of a subscale payload fairing

Keith Denoyer, Steven Griffin, Dino Sciulli

Proceedings Volume 3329, (1998) https://doi.org/10.1117/12.316896

KEYWORDS: Acoustics, Composites, Actuators, Sensors, Bandpass filters, Aerospace engineering, Space operations, Feedback control, Analytical research, Feedback loops

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During launch, spacecraft experience severe acoustic and vibration loads. Acoustic loads are primarily transmitted through the shroud or payload fairing of the launch vehicle. In recent years, there has been a trend towards using lighter weight and extremely stiff structures such as sandwich construction and grid-stiffened composites in the manufacturing of payload fairings. While substantial weight savings can be achieved using these materials, the problem of acoustic transmission is exacerbated. For this reason, the Air Force Research Laboratory has been actively engaged in vibroacoustic research aimed at reducing the acoustic and vibration levels seen by payloads during launch. This paper presents experimental results for the simultaneous structural and acoustic cavity mode control of a sub-scale composite isogrid payload fairing structure. In this experiment, actuation is performed through the use of both an internal speaker as well as piezoceramic strain actuators located on the outer skin of the composite structure. Sensing is accomplished using a microphone as well as a piezoelectric strain sensor. The control approach presented in this paper is a decentralized frequency domain approach which makes use of a series of independent control loops. One loop uses the microphone and speaker, while additional loops use the piezoelectric sensors and actuators. The control algorithm consists of independent second-order Positive Position Feedback (PPF) controllers tuned to reduce the magnitude of each cavity mode. A PPF filter in conjunction with an extremely sharp bandpass filter is used on the structural mode of limit spillover. This approach leads to a substantial reduction in the acoustic transmission in the range of 0 - 800 Hz. Transmission coincident with the primary cavity modes of the system are reduced in magnitude by 26 and 9 dB respectively while the structural model that is responsible for the majority of transmission is reduced by approximately 7 dB.

Proceedings Article | 27 July 1998 Paper

Microcontroller-based implementation of adaptive structural control

Donald Leo, Steven Griffin

Proceedings Volume 3329, (1998) https://doi.org/10.1117/12.316885

KEYWORDS: Digital filtering, Microcontrollers, Algorithm development, Sensors, Amplifiers, Feedback control, Actuators, Adaptive control, Analog filtering, Signal processing

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Proceedings Article | 27 July 1998 Paper

Experimental sensor and actuator location procedure for control of dynamically complex smart structures

Steven Griffin, Keith Denoyer

Proceedings Volume 3329, (1998) https://doi.org/10.1117/12.316936

KEYWORDS: Sensors, Actuators, Ferroelectric polymers, Motion models, Smart sensors, Acoustics, Modal analysis, Smart structures, Motion measurement, Error analysis

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Proceedings Article | 6 May 1994 Paper

Smart aerodynamic control surface actuator

Steven Griffin, Sathya Hanagud

Proceedings Volume 2190, (1994) https://doi.org/10.1117/12.175174

KEYWORDS: Actuators, Bandpass filters, Linear filtering, Aerodynamics, Feedback control, Composites, Sensors, Ferroelectric materials, Signal analyzers, Curium

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Proceedings Article | 8 September 1993 Paper

ACESA active-member damping performance

Allen Bronowicki, John Innis, Robert Betros, Steven Kuritz, Steven Griffin

Proceedings Volume 1917, (1993) https://doi.org/10.1117/12.152813

KEYWORDS: Actuators, Sensors, Ferroelectric materials, Control systems, Intelligence systems, Analog electronics, Smart structures, Vibration control, Electronics, Digital filtering

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Proceedings Article | 1 December 1990 Paper

Astronautics laboratory smart structures/skins program overview

Steven Griffin

Proceedings Volume 1370, (1990) https://doi.org/10.1117/12.24863

KEYWORDS: Sensors, Composites, Actuators, Smart structures, Fiber optics sensors, Fiber optics, Control systems, Astronomical engineering, Prototyping, Skin

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Showing 5 of 20 publications

Proceedings Volume Editor (6)

SPIE Conference Volume | 1 September 2016

Industrial and Commercial Applications of Smart Structures Technologies 2016

SPIE Conference Volume | 12 May 2015

Industrial and Commercial Applications of Smart Structures Technologies 2015

SPIE Conference Volume | 5 May 2014

Industrial and Commercial Applications of Smart Structures Technologies 2014

SPIE Conference Volume | 18 April 2013

Industrial and Commercial Applications of Smart Structures Technologies 2013

SPIE Conference Volume | 19 April 2012

Industrial and Commercial Applications of Smart Structures Technologies 2012

Showing 5 of 6 publications

Conference Committee Involvement (14)

Smart Structures and NDE for Industry 4.0, Smart Cities, and Energy Systems

27 April 2020 | Online Only, California, United States

Smart Structures and NDE for Energy Systems and Industry 4.0

4 March 2019 | Denver, Colorado, United States

Smart Structures and NDE for Industry 4.0

5 March 2018 | Denver, Colorado, United States

Industrial and Commercial Applications of Smart Structures Technologies XI

26 March 2017 | Portland, Oregon, United States

Industrial and Commercial Applications of Smart Structures Technologies X

21 March 2016 | Las Vegas, Nevada, United States

Industrial and Commercial Applications of Smart Structures Technologies IX

9 March 2015 | San Diego, California, United States

Industrial and Commercial Applications of Smart Structures Technologies VIII

11 March 2014 | San Diego, California, United States

Industrial and Commercial Applications of Smart Structures Technologies VII

10 March 2013 | San Diego, California, United States

Industrial and Commercial Applications of Smart Structures Technologies VI

12 March 2012 | San Diego, California, United States

Industrial and Commercial Applications of Smart Structures Technologies V

7 March 2011 | San Diego, California, United States

Industrial and Commercial Applications of Smart Structures Technologies V

7 March 2011 | San Diego, California, United States

Industrial and Commercial Applications of Smart Structures Technologies IV

8 March 2010 | San Diego, California, United States

Industrial and Commercial Applications of Smart Structures Technologies III

9 March 2009 | San Diego, California, United States

Industrial and Commercial Applications of Smart Structures Technologies II

10 March 2008 | San Diego, California, United States

Showing 5 of 14 Conference Committees

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