This paper proposes numerical methods for solving hybrid weakly singular integro-differential equations of the second kind. The terms in these equations are in the following order: derivative term of a state, integro-differential term of a state with a weakly singular kernel, a state, integral term of a state with a smooth kernel, and force. The original class of weakly singular integro-differe...

In the German Aerospace Center, DLR, an internal project has been launched to investigate different UCAV configurations. One aspect, covered by the Institute of Aeroelasticity and the Institute of Aerodynamics and Flow Technology, is the wind tunnel test of a UCAV wing in subsonic and transonic flow. The model shall show measurable static aeroelastic deformations. Main goals of the tests will b...

A quantitative analysis of coupling between systems of equations is introduced. This analysis is then applied to problems in multidisciplinary analysis, sensitivity, and optimization. For the sensitivity and optimization problems both multidisciplinary and single discipline feasibility schemes are considered. In all these cases a "convergence factor" is estimated in terms of the Jacobians and H...

Composite materials allow to tailor the elastic properties of a structure. In aeroelasticity, this opens up possibility passively enhance coupled aerostructural characteristics. work, design composite wing is addressed with aim alleviate static and dynamic aeroelastic loads; these two objectives are quantified by root-bending-moment in high load-factor condition deformation amplitude under gust...

New approaches to multidisciplinary design optimization have been developed and demonstrated in a NASA Langley funded project to look at a particularly challenging aeronautics problem – High Speed Civil Transport Aeroelastic Wing Design. In particular, the problem is how to incorporate key multidisciplinary information and knowledge as it becomes available. This problem results from such inform...

A simple, but scientifically rigorous, framework is proposed for estimation of effectiveness of elastic materials for the reduction of pressure fluctuations. The framework employs the intrinsic correspondence between a transformation of vorticity perturbations into acoustic waves at the elastic boundary and the conversion of transverse (shear) waves to radiated longitudinal (pressure) waves. Th...

This paper presents a distributed parameter optimal control method. The state-space equation of wing bending-torsion aeroelasticity is formulated using aeroelastic differential operators. The optimal control problem is formulated as linear quadratic regulator in a Hilbert inner product space. The solution to the optimal control problem leads to a differential operator Ricatti equation. Using a ...

In this work the aeroelastic stability of long-span bridge decks is numerically investigated. A simulation model is presented by which the aerodynamic fields and the structural motion are simultaneously and jointly simulated. The bridge deck is schematised as a bidimensional rigid body subject to elastic restraints corresponding to the torsional and the vertical degree of freedom, and the ALE f...

In this contribution, a new and efficient multivariate interpolation scheme is presented which is designed for large-scale coupling problems in the field of numerical aeroelasticity. The scheme is based upon a local application of radial basis functions (RBFs). The new method is tested in several numerical aeroelastic computations, and compared to a competing, widely used global approach. The i...