More cost-effective structural design for aircraft
Thin-walled carbon fibre reinforced polymer (CFRP) composites are well known for their ability to absorb energy and resist buckling. They are highly regarded within the aircraft industry due to the combination of these characteristics with their light weight. Weight reduction leads to major cost savings in fuel consumption. While it is clear that these materials tolerate repeated buckling without change in their behaviour, the extent to which they can be subjected to stress without being severely damaged had not been previously addressed. Current simulation tools do not allow for collapse of aircraft structures, resulting in overly conservative design specifications. The ‘Improved material exploitation at safe design of composite airframe structures by accurate simulation of collapse’ (Cocomat) project was undertaken to conduct a thorough collapse analysis of composite CFRP aircraft panels and develop accurate simulations of collapse. The researchers compared the knowledge of partners regarding collapse analysis of undamaged and damaged panels to identify deficiencies in existing simulation software. With this in mind, they developed degradation models and designed test panels. They created improved collapse simulation methods focused on advanced finite element models geared toward certification as well as fast design tools for reducing design and analysis time. They then enhanced the experimental database with testing of undamaged and damaged panels. Finally, they developed design guidelines validated by industrial partners. In summary, the Cocomat project significantly extended the existing database of CFRP materials properties to include collapse of undamaged and damaged structures under static and low-cycle loading conditions. The researchers delivered important simulation tools for fast design and slower certification procedures as well as guidelines for design considerations. Thus, the Cocomat project provided important advances in the design of CFRP composite fuselage structures. The outcomes should lead to important reductions in development and operating costs for the European aircraft industry, translating to enhanced competitiveness, reduced fuel consumption and a healthier planet.