Data modelling ensures aircraft component viability
Thermoplastics are used in many industries because of their strength, durability, and fatigue resistance. They also offer cost-effectiveness and enhanced sustainability due to their recyclability. “Unlike conventional thermosets, thermoplastics can be melted and remoulded multiple times,” notes TREAL project coordinator Albert Turon from the AMADE research group at the University of Girona in Spain. In fact, they can be melted and recast almost indefinitely, helping to remove plastic from industrial waste streams.
Thermoplastic composites for aerospace
The TREAL project was launched to help the aerospace sector move towards more fully exploiting the potential of these materials. This was achieved by developing new analysis models to predict the behaviour of composites with thermoplastics, and creating a platform of numerical testing methodologies that manufacturers and designers could then use. “Our goal was to build a reliable virtual modelling platform, capable of efficiently predicting all the damage and failure modes of these new thermoplastic materials,” says Turon. “One of the main barriers to the widespread adoption of thermoplastics has been performance considerations, and the difficulties of establishing efficient manufacturing processes.”
Reliability-based numerical material analysis
The project began by manufacturing high-quality thermoplastic panels for aircraft, and developing an experimental test protocol for these, i.e. identifying allowable limits of stress, strain or stiffness for certain aircraft configurations and conditions. In parallel, a novel numerical thermoplastic material damage model was developed, designed to accurately predict the damage and failure mechanisms of these new materials. The ultimate goal was to demonstrate that such reliability-based numerical analysis could eventually replace – or at least reduce – the need for expensive and time-consuming physical structural testing. A wide range of experimental tests were performed on novel thermoplastic composites to understand the behaviour and allowable limits. The numerical models were then validated, to see how accurately they could predict the mechanical behaviour of these materials.
Uncertainty quantification and management in aircraft design
TREAL was successful in defining an efficient methodology for determining ‘design allowables’ based on simulated approaches. “In the TREAL project, we were able to implement what is called uncertainty quantification and management (UQM) along the whole development chain,” adds Aravind Sasikumar from the University of Girona, who was the UQM leader in the project. “This went from quantifying uncertainties about material properties, to developing accurate analysis tools and procedures to efficiently propagate them and obtain reliable design allowables. This is critical information for material design engineers and aircraft manufacturers, in order to design next-generation aircraft with the required safety.” To make these findings accessible, the different analysis methods developed by the team were consolidated onto a software platform in Digimat. Digimat is a state-of-the-art multiscale material modelling platform, which helps engineers to design and optimise composite materials in a fast and cost-effective way. The next step is to fully integrate these numerical analysis tools into UQM processes along the different phases of new aircraft component development. “The approach we developed will help to reduce the product development lead time, reduce the magnitude of extensive experimental campaigns and increase confidence in identified limits of stress, strain or stiffness,” says Sasikumar. “Our hope is that this virtual data modelling will eventually be integrated into the design of next-generation aircraft.”
Keywords
TREAL, aircraft, aerospace, thermoplastics, composites, UQM, Digimat
