Dr. Douglas E. Adams Profile

Dr. Douglas E. Adams

Professor at Vanderbilt Univ

SPIE Involvement:

Author

Publications (17)

Proceedings Article | 20 April 2016 Paper

In-situ material state monitoring using embedded CdSe quantum dots

Cole Brubaker, Talitha Frecker, Ian Njoroge, Dylan Shane, Christine Smudde, Sandra Rosenthal, G. Kane Jennings, Douglas Adams

Proceedings Volume 9803, 980316 (2016) https://doi.org/10.1117/12.2218351

KEYWORDS: Nanocrystals, Structural health monitoring, Nondestructive evaluation, Sensors, Composites, Quantum dots, Smart materials, Cadmium, Optical spheres, Custom fabrication, Aluminum, Epoxies, Fiber coatings, Spectroscopy

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Proceedings Article | 20 April 2012 Paper

Pulse thermography for quantitative nondestructive evaluation of sound, de-mineralized and re-mineralized enamel

Masatoshi Ando, Nathan Sharp, Douglas Adams

Proceedings Volume 8348, 83480S (2012) https://doi.org/10.1117/12.914371

KEYWORDS: Teeth, Thermography, Dental caries, Crystals, Data modeling, Thermal modeling, Cameras, Minerals, Lamps, Thermal imaging cameras

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Proceedings Article | 18 April 2011 Paper

Inspection for kissing bonds in composite materials using vibration measurements

Douglas Adams, Nathan Sharp, Noah Myrent, Ronald Sterkenburg

Proceedings Volume 7983, 79830W (2011) https://doi.org/10.1117/12.878680

KEYWORDS: Composites, Inspection, Vibrometry, Actuators, Epoxies, Ultrasonics, Damage detection, Head, Detection and tracking algorithms, Nondestructive evaluation

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Proceedings Article | 15 April 2011 Paper

Damage detection for health monitoring of ground vehicle through active probing of vehicle response

Alan Meyer, Douglas Adams

Proceedings Volume 7981, 79813P (2011) https://doi.org/10.1117/12.880153

KEYWORDS: Damage detection, Control systems, Lawrencium, Sensors, Actuators, Data modeling, Data acquisition, Transducers, Safety, Motion models

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Proceedings Article | 12 April 2010 Paper

Theoretical analysis of acceleration measurements in a model of an operating wind turbine

Jonathan White, Douglas Adams, Mark Rumsey

Proceedings Volume 7643, 76431F (2010) https://doi.org/10.1117/12.847779

KEYWORDS: Aerodynamics, Actuators, Turbulence, Sensors, Motion models, Reliability, Wind energy, 3D modeling, Structural dynamics, Wind turbine technology

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Wind loading from turbulence and gusts can cause damage in horizontal axis wind turbines. These unsteady loads and the resulting damage initiation and propagation are difficult to predict. Unsteady loads enter at the rotor and are transmitted to the drivetrain. The current generation of wind turbine has drivetrain-mounted vibration and bearing temperature sensors, a nacelle-mounted inertial measurement unit, and a nacelle-mounted anemometer and wind vane. Some advanced wind turbines are also equipped with strain measurements at the root of the rotor. This paper analyzes additional measurements in a rotor blade to investigate the complexity of these unsteady loads. By identifying the spatial distribution, amplitude, and frequency bandwidth of these loads, design improvements could be facilitated to reduce uncertainties in reliability predictions. In addition, dynamic load estimates could be used in the future to control high-bandwidth aerodynamic actuators distributed along the rotor blade to reduce the saturation of slower pitch actuators currently used for wind turbine blades. Local acceleration measurements are made along a rotor blade to infer operational rotor states including deflection and dynamic modal contributions. Previous work has demonstrated that acceleration measurements can be experimentally acquired on an operating wind turbine. Simulations on simplified rotor blades have also been used to demonstrate that mean blade loading can be estimated based on deflection estimates. To successfully apply accelerometers in wind turbine applications for load identification, the spectral and spatial characteristics of each excitation source must be understood so that the total acceleration measurement can be decomposed into contributions from each source. To demonstrate the decomposition of acceleration measurements in conjunction with load estimation methods, a flexible body model has been created with MSC.ADAMS© The benefit of using a simulation model as opposed to a physical experiment to examine the merits of acceleration-based load identification methods is that models of the structural dynamics and aerodynamics enable one to compare estimates of the deflection and loading with actual values. Realistic wind conditions are applied to the wind turbine and used to estimate the operational displacement and acceleration of the rotor. The per-revolution harmonics dominate the displacement and acceleration response. Turbulent wind produces broadband excitation that includes both the harmonics and modal vibrations, such as the tower modes. Power Spectral Density estimates of the acceleration along the span of the rotor blades indicate that the edge modes may be coupled to the second harmonic.

Proceedings Article | 9 April 2009 Paper

Damage detection in sandwich composite materials using laser vibrometry in conjunction with nonlinear system identification

Sara Underwood, David Koester, Douglas Adams

Proceedings Volume 7295, 72952I (2009) https://doi.org/10.1117/12.815817

KEYWORDS: Composites, Actuators, Damage detection, Vibrometry, Complex systems, Velocity measurements, 3D scanning, Inspection, 3D modeling, Dynamical systems

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Proceedings Article | 8 April 2009 Paper

Operational load estimation of a smart wind turbine rotor blade

Jonathan White, Douglas Adams, Mark Rumsey

Proceedings Volume 7295, 72952D (2009) https://doi.org/10.1117/12.815802

KEYWORDS: Sensors, Wind energy, Error analysis, Chromium, Medium wave, Solar energy, Actuators, Damage detection, Fiber optics sensors, Wind turbine technology

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Proceedings Article | 10 April 2008 Paper

Implementation of nonlinear acoustic techniques for crack detection in a slender beam specimen

Muhammad Haroon, Douglas Adams

Proceedings Volume 6935, 69350P (2008) https://doi.org/10.1117/12.773917

KEYWORDS: Modulation, Acoustics, Frequency modulation, Nonlinear optics, Actuators, Environmental sensing, Interfaces, Electronics, Ultrasonics, Signal detection

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Proceedings Article | 11 April 2007 Paper

Identification of damage in a suspension component using narrowband and broadband nonlinear signal processing techniques

Muhammad Haroon, Douglas Adams

Proceedings Volume 6532, 65320Y (2007) https://doi.org/10.1117/12.716644

KEYWORDS: Complex systems, Signal processing, Data modeling, Nonlinear optics, Systems modeling, Autoregressive models, Data processing, Nonlinear dynamics, Mechanical engineering, Nondestructive evaluation

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Proceedings Article | 11 April 2007 Paper

Quasi-active, minimal-sensing load and damage identification and quantification techniques for filament-wound rocket motor casings

Nick Stites, Carlos Escobar, Jonathan White, Douglas Adams, Matt Triplett

Proceedings Volume 6532, 65321E (2007) https://doi.org/10.1117/12.715789

KEYWORDS: Missiles, Rockets, Composites, Inverse problems, Data modeling, Error analysis, Systems modeling, Platinum, Biological research, Model-based design

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Proceedings Article | 15 March 2006 Paper

Crack detection in a wheel end spindle using wave propagation via modal impacts and piezo actuation

Spencer Ackers, Ronald Evans, Timothy Johnson, Harold Kess, Jonathan White, Douglas Adams, Pam Brown

Proceedings Volume 6177, 61770B (2006) https://doi.org/10.1117/12.661570

KEYWORDS: Spindles, Actuators, Finite element methods, Wave propagation, Data modeling, Clocks, Nondestructive evaluation, Aluminum, Metals, Human-machine interfaces

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Proceedings Article | 15 March 2006 Paper

Locating and quantifying ceramic body armor impact forces on a compliant torso using acceleration mapping

Adam Cardi, Douglas Adams, Shawn Walsh

Proceedings Volume 6177, 617714 (2006) https://doi.org/10.1117/12.658245

KEYWORDS: Ceramics, Inverse problems, Error analysis, Transducers, Sensors, System identification, Interference (communication), Safety, Data acquisition, Metals

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Proceedings Article | 9 May 2005 Paper

Identification of damage in a standoff metallic thermal protection system panel subjected to combined thermo-acoustic excitation

R. Jason Hundhausen, Douglas Adams, Mark Derriso

Proceedings Volume 5768, (2005) https://doi.org/10.1117/12.601586

KEYWORDS: Acoustics, Structural health monitoring, Infrared radiation, Lamps, Temperature metrology, Thermography, System identification, Inspection, Damage detection, Data acquisition

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Proceedings Article | 26 July 2004 Paper

Structural damage identification using embedded sensitivity functions

Timothy Johnson, Chulho Yang, Douglas Adams, Sam Ciray

Proceedings Volume 5390, (2004) https://doi.org/10.1117/12.541741

KEYWORDS: Complex systems, Structural health monitoring, Data modeling, Diagnostics, Systems modeling, Computing systems, Corrosion, Smart materials, Damage detection, Sensors

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Proceedings Article | 1 August 2003 Paper

Madhura Nataraju, Timothy Johnson, Douglas Adams

Proceedings Volume 5049, (2003) https://doi.org/10.1117/12.484028

KEYWORDS: Complex systems, Data modeling, Stochastic processes, Structural health monitoring, Diagnostics, Systems modeling, Environmental sensing, Aerodynamics, Nonlinear dynamics, Failure analysis

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Environmental and operational variability due to changes in the excitation or any other variable can mimic or altogether obscure evidence of structural defects in measured data leading to false positive/negative diagnoses of damage and conservative/tolerant predictions of remaining useful life in structural health monitoring system. Diagnostic and prognostic errors like these in many types of commercial and defense-related applications must be eliminated if health monitoring is to be widely implemented in these applications. A theoretical framework of "dynamic similiarity" in which two sets of mathematical operators are utilized in one system/data model to distinguish damage from nonlinear, time-varying and stochastic events in the measured data is discussed in this paper. Because structural damage initiation, evolution and accumulation are nonlinear processes, the challenge here is to distinguish damage from nonlinear, time-varying and stochastic events in the measured data is discussed in this paper. Because structural damage initiation, evolution and accumulation are nonlinear processes, the challenge here is to distinguish abnormal from normal nonlinear dynamics, which are accentuated by physically or statistically non-stationary events in the operating environment. After discussing several examples of structural diagnosis and prognosis involving dynamic similarity, a simplifeid numerical finite element model of a helicopter blade with time-varying flexural stiffness on a nonlinear aerodynamic elastic foundation that is subjected to a stochastic base excitation is utilized to introduce and examine the effects of dynamic similarity on health monitoring systems. It is shown that environmental variability can be distinguished from structural damage using a physics-based model in conjunction with the dynamic similarity operators to develop more robust damage detection algorithms, which may prove to be more accurate and precise when operating conditions fluctuate.

Proceedings Article | 16 July 2002 Paper

Nonlinear damage models for diagnosis and prognosis in structural dynamic systems

Douglas Adams

Proceedings Volume 4733, (2002) https://doi.org/10.1117/12.475507

KEYWORDS: Systems modeling, Dynamical systems, Diagnostics, Structural dynamics, Complex systems, Structural health monitoring, Nondestructive evaluation, Nonlinear dynamics, Data modeling, Composites

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Proceedings Article | 11 June 2002 Paper

Application of frequency domain ARX features for linear and nonlinear structural damage identification

Douglas Adams, Charles Farrar

Proceedings Volume 4702, (2002) https://doi.org/10.1117/12.469872

KEYWORDS: Autoregressive models, Data modeling, Complex systems, Structural health monitoring, Diagnostics, Buildings, Systems modeling, Statistical modeling, Nonlinear dynamics, Feature extraction

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