Energetic analysis of fragmentation mechanisms and dynamic delamination modelling in CFRP composites

This paper deals with the understanding and the numerical simulation of complex dissipative phenomena involved in composite absorbers for two main degradation modes: the fragmentation and the delamination modes. Fragmentation is the last step of degradation in pure compression leading to total failure of a laminate and for CFRP it is mainly initiated by a microbuckling mechanism, which is dependant on the microstructural imperfections. The dissipated energies associated to the fragment creation are evaluated through micromodelling approaches and contrary to expectations, these energies seem to be insensitive to microscopic parameters. A Weibull density knowledge on peak load and dissipated energy is also proposed. On the other hand, computation control on the delamination process has been investigated. Numerical sensitivities are justified, thanks to analytical approaches and physical-based mesh criteria are proposed for classical propagation tests. Some quasi-static experiments have been performed and good accuracy is obtained with the model. All these results give perspectives to implement delamination and fragmentation interactions at mesoscale within an absorber-like configuration.