Periodic Reporting for period 3 - ACASIAS (Advanced Concepts for Aero-Structures with Integrated Antennas and Sensors)
Reporting period: 2020-06-01 to 2021-05-31
CO2 and NOX emissions of international air traffic must be reduced, so that aviation becomes more sustainable. This requires innovative technologies that reduce aircraft fuel consumption. The ACASIAS project takes up this challenge by improving aerodynamic performance of aircraft and by facilitating the introduction of fuel-efficient engines such as Counter-Rotating Open Rotors (CROR).
ACASIAS improves the aerodynamics through conformal and structural integration of antennas into innovative aerostructures. Nowadays installed aircraft antennas are protruding structures, generating turbulence & aerodynamic drag, thus increasing fuel consumption. Currently available Ku-band satellite antennas still require exterior installation on the fuselage, which needs a protective radome, affecting aerodynamics, which may result in higher fuel consumption up to 4%. Hence, the conformal flush integration of a Ku-band SATCOM antenna will reduce the drag and the emission of CO2 & NOX. Furthermore, structurally integrated antennas reduce the risk of damaging protruding antennas, and therefore ACASIAS will also contribute to the reduction of maintenance costs and minimize operational delays.
CROR propulsion systems are a promising concept to reach a resource efficient transport, allowing up to 25% fuel saving, but the CROR engines have a main disadvantage: they produce annoying multi-harmonic noise leading to high sound pressure levels in the cabin. In ACASIAS a lining panel with an integrated Active Structural Acoustic Control (ASAC) system is developed with the aim to reduce these noise levels. The availability of this lining panel will facilitate the installation of CROR engines.
The multidisciplinary ACASIAS develops four innovative aircraft structures with multifunctional capabilities:
• Composite ortho-grid stiffened fuselage panel for integrating Ku-band SATCOM antenna tiles.
• Sandwich lining panel for reducing CROR engine cabin noise.
• Smart winglet with integrated Very High Frequency (VHF) communication antenna.
• Fibre Metal Laminate panel (FML) with integrated VHF communication antenna and integrated Global Navigation Satellite System (GNSS) antenna.
ACASIAS brings together 11 partners from 6 countries covering the three main disciplines required: composite structures, advanced antennas & miniaturised sensors in a multidisciplinary project.
ACASIAS improves the aerodynamics through conformal and structural integration of antennas into innovative aerostructures. Nowadays installed aircraft antennas are protruding structures, generating turbulence & aerodynamic drag, thus increasing fuel consumption. Currently available Ku-band satellite antennas still require exterior installation on the fuselage, which needs a protective radome, affecting aerodynamics, which may result in higher fuel consumption up to 4%. Hence, the conformal flush integration of a Ku-band SATCOM antenna will reduce the drag and the emission of CO2 & NOX. Furthermore, structurally integrated antennas reduce the risk of damaging protruding antennas, and therefore ACASIAS will also contribute to the reduction of maintenance costs and minimize operational delays.
CROR propulsion systems are a promising concept to reach a resource efficient transport, allowing up to 25% fuel saving, but the CROR engines have a main disadvantage: they produce annoying multi-harmonic noise leading to high sound pressure levels in the cabin. In ACASIAS a lining panel with an integrated Active Structural Acoustic Control (ASAC) system is developed with the aim to reduce these noise levels. The availability of this lining panel will facilitate the installation of CROR engines.
The multidisciplinary ACASIAS develops four innovative aircraft structures with multifunctional capabilities:
• Composite ortho-grid stiffened fuselage panel for integrating Ku-band SATCOM antenna tiles.
• Sandwich lining panel for reducing CROR engine cabin noise.
• Smart winglet with integrated Very High Frequency (VHF) communication antenna.
• Fibre Metal Laminate panel (FML) with integrated VHF communication antenna and integrated Global Navigation Satellite System (GNSS) antenna.
ACASIAS brings together 11 partners from 6 countries covering the three main disciplines required: composite structures, advanced antennas & miniaturised sensors in a multidisciplinary project.
WP1 (System specification): requirements for the four innovations were defined as well as the criteria for assessing their performance; provided inputs for WP2 to WP6.
WP2 (Smart SATCOM fuselage panel): novel fuselage panel was developed for the conformal & structural integration of a phased array antenna for satellite communication. The work resulted in the eco-friendly manufacturing of a composite stiffened fuselage panel with a Glass Fibre Reinforced Polymer (GFRP) window embedded in a Carbon Fibre Reinforced Polymer (CFRP) skin, stiffened at the inner side by a regular orthogrid cell structure with CFRP ribs. The fuselage panel was subject to fatigue & ultimate loads which occur during the life time of an aircraft. The overall strength of the panel was more than required. The novel panel can be used for the integration of antenna tiles inside the fuselage, which was verified by measuring the performance of an installed Ku-band antenna tile developed & manufactured.
WP3 (Smart Active Acoustic lining panel): sandwich lining panel was developed for the reduction of CROR noise inside the cabin. The work resulted in the definition of an industrial process for the manufacturing of a lining panel, which is made ”active” by conformal integration of sensors, actuators & wiring in order to control its structural vibrations & therefore its sound radiation into the cabin. The active lining was installed in front of an A380 fuselage panel. The reduction of CROR noise was measured in the acoustic transmission loss test facility of DLR to be 16 dB. Further development of this active lining is foreseen in collaboration with Diehl Aviation.
WP4 (Smart Winglet): integration of a VHF antenna in a composite winglet, with CFRP skin & an embedded GFRP window to allow radiation of the VHF antenna that was integrated as a flexible Printed Circuit Board foil, sandwiched in the foam filling of the winglet. For the manufacturing of the winglet an industrial out-of-autoclave process with self-heated CFRP moulds was defined & produced. The full-scale tests proved sufficient strength of the winglet structure subject to limit & quasi-static loads simulated bird strike event. Antenna measurements have shown that the standalone winglet prototype with integrated VHF antenna satisfies the set RF requirements. The smart winglet was designed to be installed on an Evektor EV-55 airplane, but the technology developed also applies to winglets of larger aircraft.
WP5 (Smart FML fuselage panel): structural integration of a VHF and a GNSS antenna in a GLARE like fuselage. The VHF antenna is created as a slot in the skin of the fuselage with an RF wave reflector mounted on the inside & an electrical feed to excite the metallic slot edges on the outside. The slot is filled up with several layers of GFRP material in order to preserve the load-bearing properties of the FML panel. The GNSS antenna features two circular discs positioned in circular holes in the outer & intermediate aluminium layers of the FML skin panel, stacked concentrically on top of each other and separated by a layer of GFPR. The work resulted in manufacturing of GLARE panels with GFRP slot and integrated antennas for structural and RF testing. The results of the tests correspond with the detailed design data. Further development of the technology is foreseen in collaboration with avionics & aircraft industry.
WP6 (Technology Assessment): Technology Assessment process has shown that the innovative structures satisfy the technical requirements & criteria established in WP1. The aerodynamic advantages of conformal & structurally integrated antennas have been investigated with estimates for fuel & weight savings & for reduction of CO2 & NOx emissions. The further development steps have been indicated to integrate, qualify & certify the innovations for CS/FAR-23 & CS/FAR-25 aircraft applications. The potential for certification of the ACASIAS innovations is considered by industry to generate enough interesting issues to continue research in this field.
WP7 (Management, Exploitation and Dissemination): ensuring management activities at all levels.
WP2 (Smart SATCOM fuselage panel): novel fuselage panel was developed for the conformal & structural integration of a phased array antenna for satellite communication. The work resulted in the eco-friendly manufacturing of a composite stiffened fuselage panel with a Glass Fibre Reinforced Polymer (GFRP) window embedded in a Carbon Fibre Reinforced Polymer (CFRP) skin, stiffened at the inner side by a regular orthogrid cell structure with CFRP ribs. The fuselage panel was subject to fatigue & ultimate loads which occur during the life time of an aircraft. The overall strength of the panel was more than required. The novel panel can be used for the integration of antenna tiles inside the fuselage, which was verified by measuring the performance of an installed Ku-band antenna tile developed & manufactured.
WP3 (Smart Active Acoustic lining panel): sandwich lining panel was developed for the reduction of CROR noise inside the cabin. The work resulted in the definition of an industrial process for the manufacturing of a lining panel, which is made ”active” by conformal integration of sensors, actuators & wiring in order to control its structural vibrations & therefore its sound radiation into the cabin. The active lining was installed in front of an A380 fuselage panel. The reduction of CROR noise was measured in the acoustic transmission loss test facility of DLR to be 16 dB. Further development of this active lining is foreseen in collaboration with Diehl Aviation.
WP4 (Smart Winglet): integration of a VHF antenna in a composite winglet, with CFRP skin & an embedded GFRP window to allow radiation of the VHF antenna that was integrated as a flexible Printed Circuit Board foil, sandwiched in the foam filling of the winglet. For the manufacturing of the winglet an industrial out-of-autoclave process with self-heated CFRP moulds was defined & produced. The full-scale tests proved sufficient strength of the winglet structure subject to limit & quasi-static loads simulated bird strike event. Antenna measurements have shown that the standalone winglet prototype with integrated VHF antenna satisfies the set RF requirements. The smart winglet was designed to be installed on an Evektor EV-55 airplane, but the technology developed also applies to winglets of larger aircraft.
WP5 (Smart FML fuselage panel): structural integration of a VHF and a GNSS antenna in a GLARE like fuselage. The VHF antenna is created as a slot in the skin of the fuselage with an RF wave reflector mounted on the inside & an electrical feed to excite the metallic slot edges on the outside. The slot is filled up with several layers of GFRP material in order to preserve the load-bearing properties of the FML panel. The GNSS antenna features two circular discs positioned in circular holes in the outer & intermediate aluminium layers of the FML skin panel, stacked concentrically on top of each other and separated by a layer of GFPR. The work resulted in manufacturing of GLARE panels with GFRP slot and integrated antennas for structural and RF testing. The results of the tests correspond with the detailed design data. Further development of the technology is foreseen in collaboration with avionics & aircraft industry.
WP6 (Technology Assessment): Technology Assessment process has shown that the innovative structures satisfy the technical requirements & criteria established in WP1. The aerodynamic advantages of conformal & structurally integrated antennas have been investigated with estimates for fuel & weight savings & for reduction of CO2 & NOx emissions. The further development steps have been indicated to integrate, qualify & certify the innovations for CS/FAR-23 & CS/FAR-25 aircraft applications. The potential for certification of the ACASIAS innovations is considered by industry to generate enough interesting issues to continue research in this field.
WP7 (Management, Exploitation and Dissemination): ensuring management activities at all levels.
The main results are multifunctional aircraft structures, i.e. load bearing structures with integrated antennas & a new lining panel with Integrated Active Acoustic Control, as well as technologies to manufacture these structures such as an industrial out-of-autoclave process with self-heated CFRP moulds & a reusable vacuum bag to support orthogrid structures during the autoclave process.
ACASIAS will bring measurable reduction of environmental impact thanks to the Smart fuselage linings with integrated ASAC system, enabling the installation of CROR engines which can reduce fuel consumption and CO2 – NOx emissions up to 25%. Additionally, aircraft with integrated antennas have reduced aerodynamic drag & can also realise up to 2% fuel & CO2 saving, & up to 3% NOx saving.
ACASIAS will bring measurable reduction of environmental impact thanks to the Smart fuselage linings with integrated ASAC system, enabling the installation of CROR engines which can reduce fuel consumption and CO2 – NOx emissions up to 25%. Additionally, aircraft with integrated antennas have reduced aerodynamic drag & can also realise up to 2% fuel & CO2 saving, & up to 3% NOx saving.