The capabilities of the FE code Abaqus can be extended by Python scripts and user written Fortran subroutines. ALE developed progressive damage models for composites in the framework of the MAAXIMUS (More Affordable Aircraft through eXtended, Integrated and Mature nUmerical Sizing) FP7 project, led by Airbus. MAAXIMUS aims at achieving the fast development and right-first-time validation of a highly optimised composite fuselage thanks to a coordinated effort between virtual structure development and composite technology.
A multi-scale damage model has been developed by ALE, which predicts ply-level damage evolution, based on the properties of the constituents, e.g. epoxy matrix and carbon fibre. Effects of voids and fibre misalignment can be taken into account. The model is analytical and therefore numerically efficient. Failure criteria are defined on constituent level and can be determined from ply or constituent strength data. The multi-scale damage model is implemented in Abaqus in combination with a user-friendly Graphical User Interface to define the necessary properties. The multi-scale damage model relies on accurate prediction of stress and strain from the underlying finite elements. For thin shell applications ALE has implemented a so-called Solid-Like Shell (SLS) element that has all the advantages of normal shell elements, but is able to predict 3D stress and strain.
The combination of solid-like shell elements and the multi-scale damage model has been demonstrated by application in simulations of stringer-stiffened composite panel tests.