Prof. Patricia A. Howell Profile

Prof. Patricia A. Howell

Engineer at NASA Langley Research Ctr

SPIE Involvement:

Author

Publications (17)

Proceedings Article | 12 April 2021 Presentation

Estimation of delamination contact resistance in composites

William Winfree, Joseph Zalameda, Patricia Howell

Proceedings Volume 11743, 117430K (2021) https://doi.org/10.1117/12.2587633

KEYWORDS: Resistance, Composites, Computed tomography, Thermal modeling, Data acquisition, Computer simulations, 3D modeling

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Proceedings Article | 4 May 2020 Presentation + Paper

Quadrupole simulations of three-dimensional structures

William Winfree, Joseph Zalameda, Patricia Howell

Proceedings Volume 11409, 114090K (2020) https://doi.org/10.1117/12.2557417

KEYWORDS: Finite element methods, Resistance, Interfaces, Inspection, Diffusion, Composites, Thermography, Matrices, Chemical elements, Heat flux

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Proceedings Article | 2 May 2019 Presentation + Paper

Quadrupole simulations of thermographic inspections of impacted composites

William Winfree, Joseph Zalameda, Patricia Howell

Proceedings Volume 11004, 110040F (2019) https://doi.org/10.1117/12.2520281

KEYWORDS: Composites, Computed tomography, Thermography, Inspection, X-ray computed tomography

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Proceedings Article | 11 May 2016 Paper

Simulation of thermographic responses of delaminations in composites with quadrupole method

William Winfree, Joseph Zalameda, Patricia Howell, K. Elliott Cramer

Proceedings Volume 9861, 98610N (2016) https://doi.org/10.1117/12.2221994

KEYWORDS: Composites, Thermography, Interfaces, Data modeling, Computer simulations, Resistance, Chemical elements, Finite element methods, Computed tomography, Solids

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Proceedings Article | 12 May 2015 Paper

Measurement of flaw size from thermographic data

William Winfree, Joseph Zalameda, Patricia Howell

Proceedings Volume 9485, 94850D (2015) https://doi.org/10.1117/12.2176292

KEYWORDS: Composites, Chemical elements, Convolution, Image processing, Finite element methods, Computed tomography, Thermography, Binary data, Time metrology, Error analysis

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Proceedings Article | 12 May 2015 Paper

Principal component analysis of thermographic data

William Winfree, K. Elliott Cramer, Joseph Zalameda, Patricia Howell, Eric Burke

Proceedings Volume 9485, 94850S (2015) https://doi.org/10.1117/12.2176285

KEYWORDS: Principal component analysis, Composites, Data modeling, Inspection, Thermal modeling, Thermography, Resistance, Data acquisition, Nondestructive evaluation, Data processing

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Proceedings Article | 21 May 2014 Paper

Computational reduction of specimen noise to enable improved thermography characterization of flaws in graphite polymer composites

William Winfree, Patricia Howell, Joseph Zalameda

Proceedings Volume 9105, 91050O (2014) https://doi.org/10.1117/12.2051356

KEYWORDS: Composites, Thermography, Inspection, Polymers, Data acquisition, Infrared imaging, Radon, Infrared radiation, Image processing, Nondestructive evaluation

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Proceedings Article | 22 May 2013 Paper

Improved sizing of impact damage in composites based on thermographic response

William Winfree, Patricia Howell, Cara A. Leckey, Matthew Rogge

Proceedings Volume 8705, 87050V (2013) https://doi.org/10.1117/12.2016946

KEYWORDS: Composites, Ultrasonics, Data acquisition, Thermography, Inspection, Diffusion, Carbon, Fiber reinforced polymers, Nondestructive evaluation, Time metrology

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Proceedings Article | 10 May 2011 Paper

Improved flaw detection and characterization with difference thermography

William Winfree, Joseph Zalameda, Patricia Howell

Proceedings Volume 8013, 80130U (2011) https://doi.org/10.1117/12.883472

KEYWORDS: Composites, Thermography, Image registration, Resistance, Polymers, Infrared radiation, Infrared imaging, Thermal modeling, Data acquisition, Inspection

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Proceedings Article | 18 April 2006 Paper

Development of an extra-vehicular (EVA) infrared (IR) camera inspection system

Michael Gazarik, Dave Johnson, Ed Kist, Frank Novak, Charles Antill, David Haakenson, Patricia Howell, John Pandolf, Rusty Jenkins, Rusty Yates, Ryan Stephan, Doug Hawk, Michael Amoroso

Proceedings Volume 6205, 62051C (2006) https://doi.org/10.1117/12.669683

KEYWORDS: Cameras, Infrared cameras, Imaging systems, Inspection, Infrared imaging, Thermography, Electronic components, Manufacturing, Thermal modeling, Infrared radiation

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Proceedings Article | 18 August 2005 Paper

Infrared on-orbit inspection of shuttle orbiter reinforced carbon-carbon using solar heating

P. Howell, W. Winfree, K. Elliott Cramer

Proceedings Volume 5880, 588009 (2005) https://doi.org/10.1117/12.615332

KEYWORDS: Inspection, Cameras, Nondestructive evaluation, Infrared cameras, Thermography, Infrared imaging, Signal to noise ratio, Infrared radiation, Principal component analysis, Heat flux

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Proceedings Article | 28 March 2005 Paper

Compression techniques for improved algorithm computational performance

Joseph Zalameda, Patricia Howell, William Winfree

Proceedings Volume 5782, (2005) https://doi.org/10.1117/12.609024

KEYWORDS: Principal component analysis, Inspection, Data modeling, Image compression, Composites, Signal to noise ratio, Nondestructive evaluation, Temperature metrology, Data processing, Image processing

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Proceedings Article | 10 November 2003 Paper

Computational analysis for thermal NDE of composites

Patricia Howell, Joseph Zalameda

Proceedings Volume 5191, (2003) https://doi.org/10.1117/12.507800

KEYWORDS: Nondestructive evaluation, Microbolometers, Diffusion, Cameras, Detection and tracking algorithms, Composites, Anisotropic diffusion, Inspection, Infrared cameras, Staring arrays

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Proceedings Article | 28 March 1995 Paper

Quantitative thermal imaging of aircraft structures

K. Elliott Cramer, Patricia Howell, Hazari Syed

Proceedings Volume 2473, (1995) https://doi.org/10.1117/12.204859

KEYWORDS: Thermography, Inspection, Corrosion, Skin, Nondestructive evaluation, Infrared imaging, Image processing, Imaging systems, Infrared radiation, Aluminum

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Aircraft structural integrity is a major concern for airlines and airframe manufacturers. To remain economically competitive, airlines are looking at ways to retire older aircraft, not when some fixed number of flight hours or cycles has been reached, but when true structural need dictates. This philosophy is known as `retirement for cause.' The need to extend the life of commercial aircraft has increased the desire to develop nondestructive evaluation (NDE) techniques capable of detecting critical flaws such as disbonding and corrosion. These subsurface flaws are of major concern in bonded lap joints. Disbonding in such a joint can provide an avenue for moisture to enter the structure leading to corrosion. Significant material loss due to corrosion can substantially reduce the structural strength, load bearing capacity and ultimately reduce the life of the structure. The National Aeronautics and Space Administration's Langley Research Center has developed a thermal NDE system designed for application to disbonding and corrosion detection in aircraft skins. By injecting a small amount of heat into the front surface of an aircraft skin, and recording the time history of the resulting surface temperature variations using an infrared camera, quantitative images of both bond integrity and material loss due to corrosion can be produced. This paper presents a discussion of the development of the thermal imaging system as well as the techniques used to analyze the resulting thermal images. The analysis techniques presented represent a significant improvement in the information available over conventional thermal imaging due to the inclusion of data from both the heating and cooling portion of the thermal cycle. Results of laboratory experiments on fabricated disbond and material loss samples are presented to determine the limitations of the system. Additionally, the results of actual aircraft inspections are shown, which help to establish the field applicability for this technique. A recent application of this technology to aircraft repairs using boron/epoxy patches is shown illustrating the flexibility of the technology.

Proceedings Article | 6 April 1993 Paper

Quantitative thermal depth imaging of subsurface damage in insulating materials

K. Elliott Cramer, Patricia Howell, William Winfree

Proceedings Volume 1933, (1993) https://doi.org/10.1117/12.141968

KEYWORDS: Thermography, Composites, Image processing, Radiometry, Video processing, Video, Data acquisition, Diffusion, Imaging systems, Infrared imaging

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Proceedings Article | 1 April 1992 Paper

Thermographic imaging of cracks in thin metal sheets

K. Elliott Cramer, William Winfree, Patricia Howell, Hazari Syed, Keith Renouard

Proceedings Volume 1682, (1992) https://doi.org/10.1117/12.58532

KEYWORDS: Image filtering, Metals, Heat flux, Aluminum, Imaging systems, Video, Image processing, Infrared imaging, Image analysis, Radiometry

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Proceedings Article | 1 March 1990 Paper

Material property measurements with post-processed thermal image data

Christopher Welch, William Winfree, D. Michele Heath, K. Elliott Cramer, Patricia Howell

Proceedings Volume 1313, (1990) https://doi.org/10.1117/12.21921

KEYWORDS: Thermal modeling, Thermography, Data modeling, Imaging systems, Nondestructive evaluation, Video, Signal to noise ratio, Convolution, Statistical analysis, Interference (communication)

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Showing 5 of 17 publications

Conference Committee Involvement (2)

Optical Diagnostics

3 August 2005 | San Diego, California, United States

Optical Diagnostics for Fluids, Solids, and Combustion II

3 August 2003 | San Diego, California, United States

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