Flexible Aircraft

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Description

Figure 1: View of the aerostructure of the flexible aircraft.

Flexible aircraft models are very challenging in civil aeronautics due to their lighter structure. Models are largely used to optimize and analyze critical phenomena in the pre-design phase. Such model can be used to monitor some dimensioning critical stress of the aircraft in response to discrete and continuous gust situations.

This benchmark contains a set of frequency-domain input-output data (computed from a high fidelity simulator)

$\{\omega_i,\Phi_i\}_{i=1}^N,$

where $\Phi_i\in\mathbb C^{92\times 1}$, represents the transfer from an input signal (gust disturbance) to measurement outputs (accelerations and moments at different coordinates of a flexible aircraft wings and tail), evaluated at varying frequencies $\omega_i\in\mathbb R$ [rad/s], for $i=1,\dots,N=421$.

Motivation

Computing responses to discrete gusts are sizing steps when designing and optimizing a new aircraft structure and geometry. Indeed, this is part of the imposed clearance certifications requested by the flight authorities. During the aircraft preliminary design phase, this clearance is done by intensive simulations, however, due to the involved model's complexity, these latter are time-consuming and imply an important computational burden. Moreover, these simulations are involved at different steps of the aircraft optimization process, e.g., by aeroelastic, flight and control engineers. In , a systematic way to fasten the gust simulation step and simplify the analysis by mean of data-driven model approximation in the Loewner framework is proposed, as well as a description of this model.

Origin

Collaboration between ONERA and DLR.

Data

The FlexibleAircraft.zip (585KB) repository contains two files.

• The dataONERA_FlexibleAircraft.mat data files
• The startONERA_FlexibleAircraft.m script file

dataONERA_FlexibleAircraft.mat contains
W : the frequency values in rad/s (real $1 \times 421$ vector). 
H : transfer function matrix evaluation at different output measurements points of the aircraft (complex $92 \times 1 \times 421$ matrix).
The transfer function matrix H represents the transfer from the  gust input to the 92 measurements gathering from
*  1--44: the local aerodynamic lift on the aerodynamic strips.
* 45--88: the local aerodynamic pitch moment on the aerodynamic strips.
* 89--92: the four generalized coordinates derivative (heave and pitch derivatives) and the first two flexible modes. 

startONERA_FlexibleAircraft.m loads and plots the data for illustration.

Contact

Charles Poussot-Vassal