Douglas E. Adams

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— Modeling and simulation environments are needed to support decision making in Navy Warfighters, which are emergent systems that pose a challenge to operations management. Ships consist of complex interconnected systems such as the infrastructure, crew, and workflow. A system-of-systems approach using agent-based modeling is applied here to develop(More)
This paper presents a robust crack detection algorithm for wind turbine blades using vibro­acoustic modulation and the area under the curve of the frequency spectrum of the sidebands. In a previous paper it was shown how the operational vibration of the turbine could be used as a pumping signal in vibro­acoustic modulation. However, the sources of the(More)
This paper presents a new technique for identifying cracks in wind turbine blades undergoing operational loads using the Vibro-Acoustic Modulation technique. Vibro-Acoustic Modulation utilizes a low frequency pumping excitation signal in conjunction with a high frequency probing excitation signal to create the modulation that is used to identify cracks.(More)
The effectiveness of many structural health monitoring techniques depends on the placement of sensors and the location of input forces. Algorithms for determining optimal sensor and forcing locations typically require data, either simulated or measured, from the damaged structure. Embedded sensitivity functions provide an approach for determining the best(More)
This is to certify that the thesis/dissertation prepared By Entitled For the degree of Is approved by the final examining committee: Chair To the best of my knowledge and as understood by the student in the Research Integrity and Copyright Disclaimer (Graduate School Form 20), this thesis/dissertation adheres to the provisions of Purdue University's "(More)
In this paper we present an application of fault identification and control reconfiguration in the context of a high performance aircraft. A second order divided difference filter is used to identify an internal leakage fault in an electrohydraulic actuator found in the aircraft elevator. The identified fault information is then utilized in the formulation(More)
A wind turbine blade's structural dynamic response is simulated and analysed with the goal of characterizing the presence and severity of a shear web disbond. Computer models of a 5 MW offshore utility-scale wind turbine were created to develop effective algorithms for detecting such damage. Through data analysis and with the use of blade measurements, a(More)
NOMENCLATURE Y nl (ω) Fourier transform of nonlinear describing function F() Fourier transform of the measured force history X() Fourier transform of measured time history µ Nonlinear coefficient, uncorrelated noise on output GXX Auto-power matrix GFX Cross-power matrix SDOF Single degree-of-freedom Uncorrelated noise on input ABSTRACT The H 2 frequency(More)
Rotor blades with embedded sensors are envisioned to provide estimators for the operational deflection of the blade for current control systems, monitors of fatigue accumulation for reduced operation and maintenance costs, and observers for next generation smart adaptive wind turbines. Smart adaptive wind turbines will have active aerodynamic load control(More)