End-of-life pathways for aircraft sandwich panels: From structural reuse to fibre recovery

Details

Supervisors

Pardoen, Thomas ; Nysten, Bernard

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil en chimie et science des matériaux, à finalité spécialisée

Abstract

enThe carbon fibre reinforced polymer (CFRP) production has grown drastically since their introduction in the late 1960s. With an expected half a million metric tonnes of waste by 2050 their environmental impact has become a major concern. In addition to the high emissions across their life cycle, this imperatively calls for viable end-of-life management solutions. Historically, research has primarily focused on the recycling of model composite materials. However, from a circular economy perspective, reuse is a more desirable strategy, as it preserves not only the mechanical and functional properties of components but also their embodied energy. Moreover, model composites fail to capture the complexity of real post-consumer waste streams, which often consist of multimaterial, multi-layered structures. This study shifts from model systems to a full-scale aerospace structural component, investigating circular solutions for refurbishing the rudder skin of an end-of-life Boeing 737-400. Two complementary scales are considered: structural reuse of the component and material reuse through recovered plies. Mechanical characterisation of the panels shows preferential degradation aligned with the principal stress directions. This results in a 15% loss in stiffness and a reduction in tensile strength, the latter being associated with matrix fatigue damage. Despite this degradation, the material still competes with metals and ceramics in terms of stiffness-to-weight ratio for a fixed thickness, while maintaining a lower overall weight. Its environmental footprint remains highly attractive, making reuse particularly relevant for applications requiring low energy consumption during the use phase. However, economic viability remains the main hurdle, mainly due to market acceptance and labour intensity. During recycling, one route effectively removes most of the residual resin and disrupts yarn alignment, while the other retains approximately 40% volatile content and exhibits surface defects such as residual paint and adhesive. These residues lead to poor resin infusion, resulting in voids and linear defects, thereby reducing overall mechanical performance. The first route, however, preserves relatively good mechanical properties despite fibre misalignment and the absence of sizing.