Abstract
An experimental and numerical analysis of the response of laminated composite plates under high-velocity impact loads of soft body gelatine projectiles (artificial birds) is presented. The plates are exposed to tensile and compressive preloads before impact in order to cover realistic loading conditions of representative aeronautic structures under foreign object impact. The modelling methodology for the composite material, delamination interfaces, impact projectile, and preload using the commercial finite element code Abaqus are presented in detail. Finally, the influence of prestress and of different delamination modelling approaches on the impact response is discussed and a comparison to experimental test data is given. Tensile and compressive preloading was found to have an influence on the damage pattern. Although this general behaviour could be predicted well by the simulations, further numerical challenges for improved bird strike simulation accuracy are highlighted.
Highlights
The application of carbon fibre-reinforced plastic (CFRP) materials in aircraft structures is ever-expanding
After successful separate validation of all model components, that is, composite and delamination model as well as bird impactor model, everything was combined in bird strike simulation models on preloaded composite plates
A large number of bird strike simulations was performed in order to represent the whole test matrix and to analyse the influence of different parameters, that is, (i) preload: compression, unloaded, and tension; (ii) impact velocity: 100 m/s, 140 m/s, and 170 m/s; (iii) impactor model: Lagrangian and Eulerian; (iv) delamination interfaces: none, 2, 6, and 12
Summary
The application of carbon fibre-reinforced plastic (CFRP) materials in aircraft structures is ever-expanding. Besides established utilisation in control surfaces or wing structures, the latest generation of commercial airliners feature a fuselage made of carbon fibre composite material Besides their well-known advantages in terms of weight-specific mechanical properties and fatigue tolerance, such structures are vulnerable against transversal impact loads, which can lead to undetectable internal damage and cracks that can reduce the strength and grow under load. Typical examples of such impact load cases with frequent occurrence are bird strike loads on composite wing leading edges or hard body impact loads from stones or runway debris being thrown against lower fuselage panels by the aircraft tires. There is a strong interest in investigating the influence of preloads on the impact response of aeronautic structures
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