Meso-scale models to analyse the interactions of damage modes in composites laminates

icaf2023 Tracking Number 140

The response of complex composite parts for primary aeronautical structures, such as rotorcraft rotors, is influenced by the evolution of different damage modes. The numerical analysis of such phenomena has been undertaken within a joint project of Politecnico di Milano and Leonardo Helicopter. The approach consists of a ply-wise bi-phasic FE model of the laminate that makes possible a representation of both delamination and intralaminar matrix damage within the elements representing an idealized matrix phase [1]. Accordingly, the coupling between intralaminar cracks and delamination can be introduced in the matrix constitutive law, without requiring meshes refined at the sub-ply level. The theoretical aspects of the approach are summarized and attention is focused on a series of application cases, to illustrate the effectiveness of the technique. The modelling of inter-intralaminar damage interactions in glass-reinforced specimens is applied to represent the saturation of transverse cracking evolution in cross-ply tensile coupons as well as to predict the failures influenced by delamination in angle-ply laminates. The interaction between transverse cracking and delamination is analysed in detail for relatively thick L-shaped carbon-reinforced laminates, also considering the role of thermal residual stress and applying different coupling methods, such as coupled damage evolution and combined criteria for damage threshold. Finally, more cases referred to hybrid glass- and carbon-reinforced laminates are considered. The results indicates the potential of the approach for the prediction of the loads required to nucleate and propagate damages in real-world structural elements with complex geometry and lay-ups. [1] Airoldi A., Mirani C., Principito L. (2020). A bi-phasic modelling approach for interlaminar and intralaminar damage in the matrix of composite laminates. Composite Structures 234; 1-19 [2] Ghiasvand S., Airoldi A., Bettini P., Mirani C. (2022). Analysis of residual stresses and interface damage propagation in hybrid composite/metallic elements monitored through optical fiber sensors. Aerospace Science and Technology,129