An investigation of the effects of small mistiming on the aeroelastic modes of bladed-disk assemblies with aerodynamic coupling between blades is presented. The cornerstone of the approach is the use and development of perturbation methods that exhibit the crucial role of the interblade coupling and yield general findings regarding mistuning effects. It is shown that blade assemblies with weak ...

In this paper, a class of multi-input/multi-output aeroelastic systems with unstructured nonlinear uncertainty is considered. By using leadingand trailing-edge control surface actuations, a continuous robust controller is proposed to suppress the aeroelastic vibrations of a nonlinearwing-sectionmodelwith plunging andpitching degrees of freedom. Under amild restriction that the system uncertaint...

Numerical simulation of aircraft’s flutter is rather expensive and time-consuming. In order to save expense and calculating time, we apply first-order approximate conditions to solve the unsteady transonic Euler equations coupled with aeroelastic equations. Assuming that the airfoil is thin and undergoes small deformation, we implement wall boundary conditions on nonmoving mean wall positions. ...

It is not easy for the system identification-based reduced-order model ROM and even eigenmode based reduced-order model to predict the limit cycle oscillation generated by the nonlinear unsteady aerodynamics. Most of these traditional ROMs are sensitive to the flow parameter variation. In order to deal with this problem, a support vector machineSVMbased ROM was investigated and the general cons...

Many authors have shown the potential mass savings that a ballute can offer for both aerocapture and entry. This mass savings could enhance or even enable many scientific and human exploration missions. Prior to flight of a ballute several technical issues need to be addressed, including aeroelastic behavior. This paper begins to address the issue of aeroelastic behavior by developing and valid...

System identification is used to develop an accurate and computationally efficient discrete-time aerodynamic model of a three-dimensional, unsteady CFD solution. This aerodynamic model is then used in place of the unsteady CFD solution in a coupled aeroelastic analysis resulting in a substantial savings in computational time. The methodology has the advantage of producing an explicit mathematic...

As aircraft wings become much more flexible due to the use of light-weight composites material, adverse aerodynamics at off-design performance can result from changes in wing shapes due to aeroelastic deflections. Increased drag, hence more fuel burn, is a potential consequence. Without means for aeroelastic compensation, the benefit of weight reduction from the use of light-weight material cou...

A study of multidisciplinary design concerning the incorporation of aeroelastic tailoring, control surface blending, and active aeroelastic wing concepts is presented. The design process incorporates response surfaces, fast probability integration and modal-basis multidisciplinary design optimization to characterize the design space. The wing box skins of a representative fighter configuration ...

Studies have shown that significant vehicle mass and cost savings are possible with the use of ballutes for aero-capture. Through NASA’s In-Space Propulsion program, a preliminary examination of ballute sensitivity to geometry and Reynolds number was conducted, and a single-pass coupling between an aero code and a finite element solver was used to assess the static aeroelastic effects. There re...

The unsteady, aerodynamically induced resonance of aircraft structures may lead to potentially destructive vibrations when left unaccounted for in flight control system design. Such aeroelastic modes are difficult to accurately predict analytically, and computational models require calibration, verification, and validation. The successful design of control systems that actively suppress aeroela...