Damage Modelling of Integral Composite Flaps under Bird Strike

Kurzfassung

The work carried out during that 6 months project aimed to model, in a comprehensive approach, the damages caused by a bird strike impact on composite flaps, using the explicit PAM-CRASH code (v2009). Some correlations were done with real bird strike testing. So far, the composite structures were dimensioned considering mainly static issues. The dynamic simulations on composite structure therefore on their earlier stages, so they require a step by step approach. Besides, the flap is made up of fabric ply laminates. A fabric ply model called Fabric composite Global ply model, based on the Ladevèze model and dedicated to such composite materials is already implemented on PAM-CRASH. However, almost nothing is given about the mathematical background on which the model hinge upon, and neither about the mean of the 41 input parameters. Thus, a significant part of the work consisted to go through the mathematical background of that model in an analytical approach, and to check the results with computations. That prior step allows to get better understanding of the Fabric composite Global ply model. Then, a building block approach has been adopted to run accurate simulations, from the basic ply modeling, to the entire flap, via in between calculations on sub-structures. From the composite material modeling, to the simulations on the overall flap structure, the following issues were studied: - Analytical study and computation of the Ladevèze Fabric Composite Global ply model (kinematic, strains, stresses, non-linear elasticity, plasticity) and input data derivation. - Fabric composite ply computation using Ladevèze Fabric Global ply and two 90° stacked UD global plies (another ply model). - Delamination issues on leading edge and T-joints. - Correlations on sub-component level. - Simulations on component level.