TITLE:

DYNAMIC AEROELASTICITY OF STRUCTURALLY NONLINEAR AIRPLANE CONFIGURATIONS USING MODALLY REDUCED LINEAR AERODYNAMIC MODELS

DATE:

Friday, October 10th, 2008

TIME:

3:30 PM

LOCATION:

GMCS 214

SPEAKER:

Luciano Demasi, Assistant Professor, Department of Aerospace Engineering and Engineering Mechanics, San Diego State University

ABSTRACT:

Linear unsteady aerodynamic panel models have been the workhorse of airplane aeroelasticity for years. In recent years a class of important nonlinear aeroelasticity problems has emerged, where unsteady aerodynamic behavior can be captured adequately by such linear methods but structural modeling has to account for nonlinear effects, local and global. This seminar will present steady state and time domain methods for integrating commonly used frequency-domain unsteady aerodynamic panel models with nonlinear finite element models for structures with geometric nonlinearities. The approach is to use the full order structural matrices to capture the nonlinear structural behavior in combination with modally reduced aerodynamic matrices calculated by existing, proven, frequency-domain unsteady aerodynamic methods, such as those implemented in current commercial codes. In the unsteady case transformation of the unsteady aereodynamic models from the frequency domain to the time domain and integration with time-domain nonlinear structural models lead to coupled fluid / structures systems of equations that can be marched forward in time.

The goal of this work is to allow aeroelastic studies of Joined-Wings and other non-conventional airplane configurations, as well as structurally optimized conventional configurations, where local or global buckling constraints may be design drivers. Compression in major lifting surfaces or sub-assemblies in such cases, even without major overall deformation, makes it necessary to model nonlinear structural behaviour in full detail, while a modal approach to the aerodynamics is still adequate and is orders of magnitude more efficient computationally than CFD.

Luciano Demasi received his M. S. and Ph. D. in Aerospace Engineering from Politecnico di Torino University, Turin, Italy. He has been a postdoctoral fellow at the University of Washington’s Department of Aeronautics and Astronautics in Seattle. Currently, he is an assistant professor at the San Diego State University’s Aerospace Engineering department. His main research interests are in the fields of Multilayered Composite Structures, Computational Solid Mechanics, Static and Dynamic Aeroelasticity, including Steady and Unsteady Aerodynamics.

HOST:

Satchi Venkatraman

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