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Aeroelastic Instability Suppression by Nonlinear Targeted Energy Transfer

Implementation of Intentional Strong Nonlinearity in Dynamics and Design Alexander F. Vakakis University of Illinois at Urbana - Champaign. Aeroelastic Instability Suppression by Nonlinear Targeted Energy Transfer.

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Aeroelastic Instability Suppression by Nonlinear Targeted Energy Transfer

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  1. Implementation of Intentional Strong Nonlinearity in Dynamics and Design Alexander F. Vakakis University of Illinois at Urbana - Champaign Aeroelastic Instability Suppression by Nonlinear Targeted Energy Transfer Research supported by AFOSR STTR Phase II Grant (in collaboration with Texas A&M Univ., NextGen Aeronautics Inc, and NES Tech Inc.) The Problem: Aircraft structures vibrate undesirably due to aerodynamic forces and maneuvering loads. This limits operations and may cause structural failure. Approach: Improve performance by reducing transient responses and eliminate limit cycle oscillation (LCO). We have explained the onset of LCO of a nonlinear rigid wing in quasi-steady flow in terms of a sequence of transient resonance captures. This provides an effective strategy for passive LCO elimination through nonlinear TET by means of introducing to the problem strongly nonlinear (nonlinearizable) stiffness elements. A nonlinear energy sink (NES) is designed to passively absorb broadband vibration energy irreversibly from a Generic Transport Wing and dissipate it, thus passively eliminating the LCO. Transonic wind tunnel tests of the design are planned by end of 2010.

  2. Adaptive Stress Wave Tailoring in Discontinuous Materials Research supported by ARO MURI grant (in collaboration with Caltech) Intruder Layer 1 f(x) ~x3/2 High frequency scattering at intruder Frequency Layer 2 x 0 Sonic Vacuum ! Time Nonlinear System Identification (NSI) of Dynamical Systems Damped Nonlinear transition on the FEP Research supported by NSF and AFOSR) Research Grants (in collaboration with New Mexico State University) The Problem: Need to identify strongly nonlinear modal interactions in dynamical systems, e.g., in fluid-structure interaction, nonlinear joints and damaged components. Approach: A method that takes into account the dependence of nonlinear dynamics on initial and forcing conditions, by adopting a global/local identification multi-scale methodology valid for strongly nonlinear modal interactions and non-smooth effects. Holds promise of broad applicability for constructing reduced order models of general classes of dynamical systems. Potential for structural health monitoring. FEP Reconstruction The Problem: Design material systems with the capacity of passive and adaptive stress wave tailoring subject to various types of external excitations. Approach: Implement essential stiffness nonlinearities by means of granular interfaces in materials to achieve adaptive stress wave tailoring in material systems through targeted energy transfer, nonlinear localization, wave redirection, and energy redistribution. This leads us to fundamental study of strongly nonlinear dynamics of periodic wave transmission in granular media with and without disorders.

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