Publications
81 results found
Wang Y, Palacios R, Wynn A, 2015, A method for normal-mode-based model reduction in nonlinear dynamics of slender structures, Computers & Structures, Vol: 159, Pages: 26-40, ISSN: 0045-7949
This paper introduces a nonlinear reduced-order modelling methodology forfinite-element models of structures with slender subcomponents and inertiarepresented by lumped masses along main load paths. The constructed modelshave dynamics described by 1-D intrinsic equations of motion, which arefurther written in modal co-ordinates. This yields finite-dimensional approximationsof the system dynamics with only quadratic nonlinearities. Evaluationof the problem coefficients is performed from static condensation of theoriginal model on the lumped masses. The method exploits the multi-pointconstraints typically used to obtain sectional loads in aircraft aeroelasticanalysis. The technique is illustrated on simple 3D structural models builtusing solid elements.
Rabey PK, Wynn A, Buxton ORH, 2015, The kinematics of the reduced velocity gradient tensor in a fully developed turbulent free shear flow, JOURNAL OF FLUID MECHANICS, Vol: 767, Pages: 627-658, ISSN: 0022-1120
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Wang Y, Wynn A, Palacios R, 2015, Nonlinear Aeroservoelastic Analysis of Flexible Aircraft Described by Large Finite-Element Models, 56th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials
Fantuzzi G, Wynn A, 2015, Construction of an Optimal Background Profile for the Kuramoto-Sivashinsky Equation using Semidefinite Programming, Physics Letters A, ISSN: 0375-9601
Wynn A, Vukov M, Diehl M, 2014, Convergence guarantees for moving horizon estimation based on the real-time iteration scheme, IEEE Transactions on Automatic Control, Vol: 59, Pages: 2215-2221, ISSN: 0018-9286
In this note, conditions are proven under which a real-time implementable moving horizon estimation (MHE) scheme is locally convergent. Specifically, the real-time iteration scheme of is studied in which a single Gauss-Newton iteration is applied to approximate the solution to the respective MHE optimization problem at each time-step. Convergence is illustrated by a challenging small scale example, the Lorenz attractor with an unknown parameter. It is shown that the performance of the proposed real-time MHE algorithm is nearly identical to a fully converged MHE solution, while its fixed execution time per sample would allow one to solve 30 000 MHE problems per second on current hardware.
Wang Y, Wynn A, Palacios R, 2014, Nonlinear Model Reduction and Aeroelastic Control of Flexible Aircraft Described by Large Finite-Element Models, 55th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
Wynn A, Wang Y, Palacios R, et al., 2013, An Energy-Preserving Description of Nonlinear Beam Vibrations in Modal Coordinates, Journal of Sound and Vibration, Vol: 332, Pages: 5543-5558, ISSN: 0022-460X
Conserved quantities are identified in the equations describing large-amplitude free vibrations of beams projected onto their linear normal modes. This is achieved by writing the geometrically-exact equations of motion in their intrinsic, or Hamiltonian, form before the modal transformation. For nonlinear free vibrations about a zero-force equilibrium, it is shown that the finite-dimensional equations of motion in modal coordinates are energy preserving, even though they only approximate the total energy of the infinite-dimensional system. For beams with constant follower forces, energy-like conserved quantities are also obtained in the finite-dimensional equations of motion via Casimir functions. The duality between space and time variables in the intrinsic description is finally carried over to the definition of a conserved quantity in space, which is identified as the local cross-sectional power. Numerical examples are used to illustrate the main results.
Wynn A, Pearson DS, Ganapathisubramani B, et al., 2013, Optimal Mode Decomposition For Unsteady Flows, Journal of Fluid Mechanics, Vol: 733, Pages: 473-503, ISSN: 0022-1120
Wang Y, Wynn A, Palacios R, 2013, Robust Aeroelastic Control of Very Flexible Wings using Intrinsic Models, 54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference, Boston, Massachusetts
Wang Y, Wynn A, Palacios R, 2013, Robust Aeroelastic Control of Very Flexible Wings using Intrinsic Models, 54th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference
Palacios R, Wang Y, Wynn A, et al., 2013, Condensation of Large Finite-Element Models for Wing Load Analysis with Geometrically-Nonlinear Effects, International Forum of Aeroelasticity and Structural Dynamics 2013, Pages: 1-25
Jacob B, Rydhe E, Wynn A, 2013, The weighted Weiss conjecture and reproducing kernel theses for generalized Hankel operators, Journal of Evolution Equations
Ronch AD, Badcock K, Wang Y, et al., 2012, Nonlinear Model Reduction for Flexible Aircraft Control Design, AIAA Atmospheric Flight Mechanics Conference
Goulart PJ, Wynn A, Pearson D, 2012, Optimal mode decomposition for high dimensional systems, 51st IEEE Conference on Decision and Control
Wynn A, Goulart P, 2011, Observer Design for Systems with an Energy Preserving Nonlinearity, with Application to Fluid Flow, 50th IEEE Conference on Decision and Control and European Control Conference
Wynn A, 2011, Sufficient conditions for weighted admissibility of operators with applications to Carleson measures and multipliers, Quarterly Journal of Mathematics, Vol: 62, Pages: 747-770
Elliott SJ, Wynn A, 2011, Composition operators on weighted Bergman spaces of a half-plane, Proceedings of the Edinburgh Mathematical Society, Vol: 54, Pages: 373-379
Wynn A, 2010, α-admissibility of observation operators in discrete and continuous time, Complex Anal. Oper. Theory, Vol: 1, Pages: 109-131
Wynn A, 2009, α-admissibility of the right-shift semigroup on L²(R₊), Systems & Control Letters, Vol: 58, Pages: 677-681
Wynn A, 2009, Counterexamples to the discrete and continuous weighted Weiss conjectures, SIAM Journal on Control and Optimization, Vol: 48, Pages: 2620-2635, ISSN: 0363-0129
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