IFT-MultiLam · Enabling Interlaminar Fracture Testing of MULTIdirectional composite LAMinates for safe and efficient structures

Enabling Interlaminar Fracture Testing of MULTIdirectional composite LAMinates for safe and efficient structures

Reducing human related environmental impact is a major societal challenge. In this context, minimisation of the aviation sector’s impact is paramount, and indeed the key goal of the European Partnership for Clean Aviation. Among the strategies to achieve such goal, one is improving structural efficiency, which would lead to weight savings, cheaper operations, and better fuel efficiency. The adoption of composite materials, notably of fibre-reinforced polymers, has already led to positive outcomes. Still, the full potential of these materials is far from being fully exploited. This is due to the complexity of the mechanical behaviour of these materials, that still need to be fully understood, often resulting in oversized structures. To improve this situation, an in-depth knowledge of composites damage mechanisms is crucial. Among these, interlaminar fracture, or delamination, is one of the most critical, so that an accurate evaluation of interlaminar fracture toughness (IFT) is key to design safe and efficient structures. As of today, standard tests to quantify IFT are restricted to specimens with unidirectional (UD) layups and where delamination is propagated parallel to the fibres direction. On the flipside, most structures are built using multidirectional (MD) laminates, where delamination may appear at any interface and propagate in any direction. In these situations, IFT may differ from that obtained by standard tests. The reason for the lack of practices to evaluate IFT in MD laminates is the complexity associated with testing MD specimens and the technical challenges associated with this. The main consequence of this is that structural performance predictive capabilities remain limited, in turn leading to design uncertainties and oversized, inefficient structures. The IFT-MultiLam Project (Enabling Interlaminar Fracture Testing of MULTIdirectional composite LAMinates for safe and efficient structures) aims to develop the knowledge and the tools needed for an accurate evaluation of IFT in MD laminates. To do so, a recently developed set of MD specimens, called Fully-Uncoupled Multidirectional (FUMD), is exploited. While these specimens have already been proven to be extremely promising, further steps toward widespread adoption are still needed. These steps constitute the objectives of the IFT-MultiLam project, and are: (i) the obtainment of a complete set of FUMD delamination specimens; (ii) the exploration of the actual testing possibilities offered by such a large set, e.g. regarding interfaces that can be tested; (iii) the development of analytical/numerical tools for the selection of the most suitable specimens for actual testing; and (iv) the experimental validation of the approach developed.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз