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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)
This paper presents a new high temperature dynamic viscosity sensor for in situ condition monitoring of engine lubricants. The sensor is used to measure the variation in the quality factor of a vibrating piezoelectric cantilever beam due to viscous damping. The sensor was used to measure the dynamic viscosity of various single and multi-grade engines oils(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)
Operations and maintenance costs for offshore wind plants are estimated to be significantly higher than the current costs for onshore wind plants. One way to reduce these costs would be to implement a structural health and prognostic management (SHPM) system as part of a condition based maintenance paradigm with smart load management. To facilitate the(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)