Weakening composite materials to make them tougher
A short summary of Daan Jonas Hottentot Cederløf's thesis "Enhanced damage tolerance of composite materials by multiple delaminations". The DACOMAT project aims to control damage formation and growth in large composite structures. This work directly contributes to both aspects: by material treatment we can control where the damage initiates; by forming multiple delaminations we can increase the laminate’s overall resistance to damage growth.
Structures made out of fibre composites such as wind turbine blades or ships are often subject to damage. Small cracks can grow between layers within the material until it no longer is able to withstand its designed loads. This damage growth ultimately ends in failure.
In this PhD thesis, weak zones were purposely included in the fibre composite material. This allowed the controlled formation of multiple damage zones. The interaction of these multiple damage zones made it more difficult for the overall damage to grow. The structure became tougher, absorbing more energy before the damaged area grew.
Tougher materials allow structures to live longer, which in the case of wind turbines, allows for a more rapid transition away from fossil fuel energy sources. Alternatively, the same structure can be made with less material, reducing the environmental burden during production and when the structure is decommissioned.