Aerospace Engineering Research Works
http://hdl.handle.net/1903/1655
2016-12-02T22:20:26ZAnelastic Behavior in Filled Elastomers Under Harmonic Loading Using Distributed Rate-Dependent Elasto-Slide Elements
http://hdl.handle.net/1903/14478
Anelastic Behavior in Filled Elastomers Under Harmonic Loading Using Distributed Rate-Dependent Elasto-Slide Elements
Hu, Wei; Wereley, Norman M.
2012-09-12T00:00:00ZImpact of Nanowires on the Properties of Magnetorheological Fluids and Elastomer Composites
http://hdl.handle.net/1903/14431
Impact of Nanowires on the Properties of Magnetorheological Fluids and Elastomer Composites
Bell, Richard C.; Zimmerman, Darin T.; Wereley, Norman M.
2010-02-01T00:00:00ZEvaluation of Particle Clustering Algorithms in the Prediction of Brownout Dust Clouds
http://hdl.handle.net/1903/11846
Evaluation of Particle Clustering Algorithms in the Prediction of Brownout Dust Clouds
Govindarajan, Bharath
A study of three Lagrangian particle clustering methods has been conducted with application to the problem of predicting brownout dust clouds that develop when rotorcraft land over surfaces covered with loose sediment. A significant impediment in performing such particle modeling simulations is the extremely large number of particles needed to obtain dust clouds of acceptable fidelity. Computing the motion of each and every individual sediment particle in a dust cloud (which can reach into tens of billions per cubic meter) is computationally prohibitive. The reported work involved the development of computationally efficient clustering algorithms that can be applied to the simulation of dilute gas-particle suspensions at low Reynolds numbers of the relative particle motion. The Gaussian distribution, k-means and Osiptsov's clustering methods were studied in detail to highlight the nuances of each method for a prototypical flow field that mimics the highly unsteady, two-phase vortical particle flow obtained when rotorcraft encounter brownout conditions. It is shown that although clustering algorithms can be problem dependent and have bounds of applicability, they offer the potential to significantly reduce computational costs while retaining the overall accuracy of a brownout dust cloud solution.
2011-08-01T00:00:00ZHigh-Frequency Nonlinear Vibrational Control
http://hdl.handle.net/1903/9440
High-Frequency Nonlinear Vibrational Control
Shapiro, Benjamin; Zinn, B. T.
This paper discusses the feasibility of high-frequency nonlinear vibrational control. Such control has the advantage that it does not require state measurement and processing capabilities that are required in conventional feedback control. Bellman et al. [1] investigated nonlinear systems controlled by linear vibrational controllers and proved that vibrational control is not feasible if the Jacobian matrix has a positive trace. This paper extends previous work to include nonlinear vibrational controllers. A stability criteria is derived for nonlinear systems with nonlinear controllers, and it is shown that a nonlinear vibrational controller can stabilize a system even if the Jacobian matrix has a positive trace.
1997-01-01T00:00:00Z