Smart intelligent aircraft structure

Lore & Background

The concept of smart intelligent aircraft structures emerged from combining 'smart structures'—which adapt to environmental conditions to increase efficiency or safety—with sophistication in materials science, information technology, measurement science, sensors, actuators, signal processing, nanotechnology, cybernetics, artificial intelligence, and biomimetics. These structures are able to sense their environment, self-diagnose their condition, and adapt to make the design more useful and efficient. The integration of system tasks into the load-carrying structure offers significant improvements in aircraft total weight, manufacturing cost, and operational cost, while also improving life cycle and reducing maintenance.

Morphing structures are a key component, addressing the compromise inherent in fixed-geometry wings optimized for a single design point. By enabling wing camber variations without aerodynamic gaps, smart intelligent structures allow conformal morphing technologies such as gapless, deformable leading edge devices and wingtip active trailing edges. These reduce drag during take-off, cruise, and landing, and can decrease airframe-generated noise. Structural health monitoring (SHM) is another component, using permanently bonded or embedded sensors to detect threats to structural integrity, differing from conventional non-destructive testing. This is particularly relevant for composite materials, which are susceptible to hidden internal flaws and increase life cycle costs due to inspection needs.

Multifunctional materials, such as nanoparticle-reinforced resins, address drawbacks of carbon fibre reinforced polymers (CFRPs) like low toughness and poor electrical conductivity. Nanoparticle reinforcement can increase fracture toughness by up to 50% and improve resin conductivity from insulator to semiconductor, enabling weight savings and simpler Electrical Structure Networks. A running project called SARISTU (Smart Intelligent Aircraft Structures), coordinated by Airbus with 64 partners from 16 European countries, focuses on integrating these technologies to achieve a 6% drag reduction, up to 6 dB(A) noise reduction, and cost reductions in SHM integration and electrical structure installation.

Reader's Guide

The significance of smart intelligent aircraft structures lies in their potential to fundamentally change aircraft design by integrating multiple functions into the load-bearing structure, thereby reducing weight, manufacturing cost, and operational cost. The article emphasizes that these structures improve the aircraft's life cycle and reduce maintenance, while morphing concepts decrease airframe noise and cruise drag, positively affecting fuel consumption and take-off fuel load. The SARISTU project, with a budget of €51,000,000 and 64 partners, targets a 6% drag reduction and up to 6 dB(A) noise reduction, with calculations suggesting the target may be exceeded, though a weight penalty must be considered. Structural health monitoring is noted as not yet mature enough for reliable application to real engineering structures, but its integration could reduce inspection costs by up to 1%, with some trials showing higher benefits. The incorporation of carbon nanotubes into resins is expected to enable weight savings of up to 3% and reduce Electrical Structure Network installation costs by up to 15%. The legacy of these technologies is their potential to enable conformal morphing and reduce life cycle costs, though the article notes that SHM systems must be designed as fail-safe components within a damage tolerance assessment scenario to achieve real cost reductions.

Did You Know?

• The SARISTU project has a total budget of €51,000,000 and involves 64 partners from 16 European countries.
• Nanoparticle reinforced resins can increase fracture toughness by up to 50% for older liquid resin infusion resins and 30% in more advanced systems.
• Structural health monitoring uses sensors permanently bonded or embedded in the structure, unlike conventional non-destructive testing.
• Over 25% of the life cycle cost of an aircraft or aerospace structure can be attributed to operation and support, involving inspection and maintenance.