Fraunhofer Institute for Material and Beam Technology IWS
Fraunhofer Institute for Material and Beam Technology IWS

HESTIA

HESTIA – Ultra-high-efficiency, sustainable fuselage shells made of thermoplastic fiber-reinforced composite for a future zero-emission aircraft

FTIR spectrum of high-performance thermoplastic polymer LM-PAEK with and without carbon fiber reinforcement shows low absorption of matrix polymer at diode laser wavelength and high absorption at CO2 laser wavelengt.
© Fraunhofer IWS
FTIR spectrum of high-performance thermoplastic polymer LM-PAEK with and without carbon fiber reinforcement shows low absorption of matrix polymer at diode laser wavelength and high absorption at CO2 laser wavelengt.
Thermally sprayed copper lattice following laser micro structuring onto a carbon fiber reinforced thermoplastic laminate shows sufficient bonding after peel-off testing.
© Fraunhofer IWS
Thermally sprayed copper lattice following laser micro structuring onto a carbon fiber reinforced thermoplastic laminate shows sufficient bonding after peel-off testing.

Motivation

The joint project HESTIA – in which Fraunhofer IGCV, IFAM, and IWS are working on one of six closely interconnected partner projects – aims to develop technological building blocks for future climate-neutral aircraft with the lowest possible material and energy consumption. To this end, components and technologies for innovative fuselage shells made of thermoplastic composite materials are to be developed. The significant weight reduction achieved in this way can effectively compensate for the additional weight of novel climate-neutral propulsion systems.

 

Aims and Procedure

Within the HESTIA project, Fraunhofer IWS is working on three research focal areas:

  1. The CONTIjoin process, developed in earlier projects for joining thermoplastic multidirectional laminate semi-finished products, is being enhanced to enable the processing of additional material types. The high absorption of the CO₂ laser radiation used in the polymer matrix offers a promising advantage in terms of thermal process control compared to solid-state and diode lasers – absorbed exclusively by the carbon fibers – which are used in conventional lay-up systems. Specifically, the potential of the technology for joining unidirectional, single-ply semi-finished products (so-called tapes, which serve as feedstock for common technologies such as Automated Fiber Placement (AFP) or for the novel material class of vitrimers) is being investigated. Vitrimers represent a hybrid between thermosets and thermoplastics.
  2. In addition, identifying alternative methods for perforating fiber-reinforced composite semi-finished products represents a central focus. The locally introduced interruption of the carbon-fiber reinforcement serves to optimize drapeability during the AFP process or during thermal forming and has so far been implemented mechanically, resulting in high tool wear.
  3. Furthermore, the contacting of the lightning protection system integrated into the aircraft’s outer skin is being investigated. Using an automatable technology chain, an electrically conductive metallic mesh layer is to be retroactively integrated into these areas of the consolidated composite. Based on previously applied laser surface functionalization of the thermoplastic composite, a firmly adhering copper layer is subsequently applied by thermal spraying.

 

Innovations and Perspectives

The technology modules further developed or newly created within HESTIA open up potential for the manufacturing and processing of thermoplastic composite materials for weight-saving design concepts. With the laser technology implemented, efficient and resource-conserving processes can be realized, thereby reducing the environmental footprint of aircraft production. In addition, their flexibility also allows them to be used in the production of semi-finished goods and components in other industrial sectors.