AEROSPACE

High build rates manufacturing is necessary to meet the cost and volume requirements of vertical take-off/landing (VTOL) aero structures and to enable ultra-efficient manufacturing of commercial aircraft. Increased automation that combines dry fiber placement of skins and spar elements, with liquid composite molding will offer a significant opportunity for markedly higher build rates and reduced energy consumption. Conventional wing design based on the assembly of several sub-components is cost prohibitive and a “one-piece” wing concept with highly integrated and co-cured/bonded structures will be the most viable solution. To reach the high level of structural/fuel efficiency, along with high damage tolerance and structural integrity, novel micro and meso-structural designs are required. VTOL wings and next-gen dry wings are subjected to complex loading conditions, with highly three-dimensional stress cases (e.g., several pylons attached), high cycle fatigue and flights at low altitudes characterized by a harsh environment (rain, hail, turbulence). To survive and operate safely in such conditions, these aerostructures will require novel microstructural concepts and innovative ply-layup scenarios aiming at delivering tough, yet stiff and strong structures capable of retaining a high structural integrity. This is to overcome the limitations of conventional design philosophies (e.g., inherent brittleness, poor damage tolerance, poor impact resistance) commonly used in aerospace, such as “hard” symmetric and balanced laminates and quasi-isotropic (e.g. 0°/45°/-45°/90°) lamination sequences.

Specifically, of VTOL structures, one of the major limitations in the airframe and wing design is the use of thin laminated structures. Compared to wing skins for commercial aircrafts where the design limiting factor is compression after impact (damage tolerance) strength of the skin (thick laminates), vertical lift wings’ load bearing capability is limited by the local buckling of the skin. This new driving requirement necessitates novel microstructural and layup solutions to increase structural efficiency of the skin, its local buckling load and the overall tolerance of the skin to large deformations experienced during buckling.

Novel microstructural concepts and innovative layup scenarios are also key to increase the structural efficiency of thicker-laminate wing section of VTOL as well as of wing designs of commercial aircrafts. For thicker laminated structures, CAI strength and other damage tolerance requirements along with notch sensitivity are some of the key design drivers. The latest developments and at-scale adoption of automated manufacturing technologies has finally created a viable avenue to deploy at scale novel non-conventional layup scenarios and microstructural solutions which have proven successful (at low TRL) in improving the driving requirements for thicker laminate section. This holds a unique opportunity to realize a new generation of ultra-efficient wing structures which would benefit from the same high-rate manufacturing process explored for VTOL structures.

In addition to wing and airframe structures, areas of application of Helicoid™ include;

• containment casing for jet engine to stop blade-off events,

• structural shields resistant to ballistic and high velocity impacts for interiors,

• nose cone protection,

• fixed leading edge to mitigate bird strike events,

• local wing reinforcements to increase safety and damage tolerance at transition regions and close of structure openings (reduced notch sensitivity).

The investigation of novel microstructural and layup scenarios tailored to meet different requirements for thin and thick-walled wing and other airframe structures hold the potential to deliver a step change in reducing material usage, increasing fuel efficiency of a broad range of aircraft platforms, and enabling the transition to new sustainable technologies such as battery and hydrogen powered aircrafts.

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