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Robust- and sustainable-by-design ultra-higH aspEct ratio wing and Airframe

Periodic Reporting for period 1 - RHEA (Robust- and sustainable-by-design ultra-higH aspEct ratio wing and Airframe)

Reporting period: 2020-07-01 to 2021-09-30

The next generation of civil transport aircraft is required to have a significantly lower emission than the current aircraft to address the severe problem of climate change. To achieve this goal, various technologies and aircraft configurations are suggested to be integrated. For example, electric/hybrid-electric propulsion systems, active flow control, active load alleviation, and novel configurations such as blended wing body are being investigated at the moment. Ultra-High Aspect Ration Wings (UHARW) are promising solutions for reducing aircraft-induced drag and hence reducing emissions. However, designing aircraft with UHARW faces serious challenges since increasing the aspect ratio negatively influences the wing structural weight and aeroelasticity.

The RHEA project is investigating intelligent solutions for realizing UHARW for civil transport aircraft. The solution of RHEA is to integrate novel airframe technologies, i.e. active laminar flow control, active load alleviation, advanced structures and materials with novel aircraft configurations, i.e. struct-braced wing and twin fuselage. However, the design of aircraft with novel configurations and novel technologies required novel design methodologies and tools. Therefore, RHEA is aiming to develop beyond state-of-the-art methods and tools to design novel aircraft with disruptive configurations and novel airframe technologies and investigate the influence on reducing emissions and noise.

Besides, the design of novel aircraft using new methodologies includes a significant level of uncertainties due to the low TRL of the technologies, lack of previous experience and data, etc. Neglecting these uncertainties might result in designs, which might not be credible. RHEA aims to address the uncertainty in technologies and methodologies via an Uncertainty Based Multidisciplinary Design Optimization approach (UMDO). Using this method for design, the best designs from a robustness point of view will be determined to minimize the vulnerabilities with respect to the uncertainties.
The main results achieved so far are:

Thorough literature review and analysis of TRL of existing and promising technologies for UHARW configurations.

Developing an entire aircraft conceptual design framework capable of clean-sheet design and sizing of strut-braced and twin-fuselage aircraft equipped with novel airframe technologies such as active flow control, active load alleviation, and advanced structures and materials.

Executing this framework for conceptual design of six different aircraft in three categories: A strut-braced and a twin-fuselage configuration for each category of short-range, mid-range, and long-range passenger aircraft.

Uncertainty characterization and sensitivity analysis of all the six reference aircraft of RHEA to investigate the robustness of these aircraft and identify the best designs from the robustness aspect.

Developing coupled-adjoint aerostructural analysis and optimization toolbox for analysis and optimization of strut-braced wing configurations.

Developing a fast method for dynamic aeroelastic analysis and optimization of very high aspect ratio (geometrically nonlinear) aircraft configurations, including strut-braced wings.

Integration of aerostructural, aeroelastics, and aerodynamics methods within a multidisciplinary design and optimisation framework.
The expected results unitl the end of the project and potential impacts are:

Robust conceptual design of UHARW aircraft in three different categories and investigating their influence on emission reduction of civil aviation.

Developing coupled-adjoint aerostructural optimization framework based on geometrically nonlinear composite structures to assess and optimize UHARW.

New methods for fast evaluation of flutter and dynamic loads around deformed geometries with non-zero steady forces have been developed and integrated in the design optimization loop.

Initial integration of data-driven approach to provide aerodynamic corrections in a fast and accurate manner.

Automatic generation of new aircraft geometry and grid for computer simulations of aircraft performance.

Expected impact on the way future MDO processes will introduce uncertainty modelling and higher-fidelity methods.

Expected impact on the economy of an MDO process and the subsequent phases of design/manufacture.
Preliminary results on conceptual design - Rendering of the mid-range mission aircraft