PROJECT TITLE: Unified FEM for Aeroelasticity Analysis of Aerospace Vehicles
TECHNICAL ABSTRACT (LIMIT 200 WORDS)
Aerospace vehicles are susceptible to aeroelasticity problems such as flutter, buffet, buzz and others. These instabilities are due to strong coupling between aerodynamic loads and a structures response. An implicit coupling procedure between CFD and structures solvers is needed to resolve numerical stiffness and an efficient grid remeshing method is required which would preserve grid smoothness and desired clustering. We propose a novel "brick analogy" for unstructured grid remeshing for the computation of aeroelasticity. Unlike in the "spring analogy", which has been previously widely used, in the proposed "brick analogy" the Navier equation is applied both to structures deformation and to unstructured deforming portion of the CFD mesh which aer all solved by FEM. To preserve the grid smoothness and orthogonality, the nonlinear, large deformation with small strain rate theory is proposed. The proposed geometrically nonlinear "brick analogy" can sustain shear deformation due to the fact that the equilibrium is set up for a solid element instead of truss. By selecting proper structures properties e.g. Young's modulus and mass for the "brick" the structure dynamics and mesh dynamics (for the fluid) can be solved simultaneously by a FEM code. This technology provides an implicit coupling procedure for aeroelasticity.
In Phase I, the proposed brick analogy methodology will be assessed for the unstructured deforming remeshing of 2D oscillating wings, cascades, and 3D wings. In Phase II, the technique will be extended to couple a general-purpose fluid code with unstructured grid capability and a FEM structure dynamics code to analyze aerospace vehicle dynamics.
POTENTIAL COMMERCIAL APPLICATIONS
Successful development of the proposed algorithms will enable the fluid and structures codes to solve multi-disciplinary problems. The developed methods will provide the capability to accurately predict aeroelastic stability in aeronautical systems, heat exchanger vibration, strumming of cables and offshore pipelines, galloping of towers and masts, and fatigue of panels. It will be useful to design superior blades and wings for new generationrotorcraft and aircraft for increased performance, reduced vibration, alleviated noise, and greater maneuverability.
NAME AND ADDRESS OF PRINCIPAL INVESTIGATOR
H.Q. Yang
CFD Research Corporation
215 Wynn Dr.
Huntsville , AL 35805 - 1926
NAME AND ADDRESS OF OFFEROR
CFD Research Corporation
215 Wynn Dr.
Huntsville , AL 35805 - 1926