In this work, a combined experimental/numerical approach is used to investigate the effect of water ingression in glass/epoxy composite specimens. Interlaminar shear (ILS) specimens were immersed at 50◦C for multiple durations and tested. Re-dried specimens were also tested. Significant strength degradation of up to 50% was found for wet specimens, while dried ones showed an irreversible decrease in strength of approximately 9%. The diffusion phenomenon was also investigated numerically in a multiscale /multiphysics framework. At the microscale, an RVE combining linear-elastic fibres, elasto-plastic resin with damage and cohesive interfaces was used. At the macroscale, a classic stress equilibrium analysis is coupled with a Fickian diffusion model, and an independent micromodel is run at each macroscopic integration point. The model was used to simulate diffusion in a short-beam specimen and regions of plastic deformation, interface failures and softening bands in the resin were identified. @en

In this work a glass/epoxy composite commonly used in wind turbine blades is exposed to a humid environment at an elevated temperature. To research the anisotropic di_usion behaviour observed in unidirectional composite specimens, experimental results of slices cut along the three directional planes of the laminate immersed in demineralised water at 50_C are coupled with numerical modelling. The weight of the slices was measured at regular intervals, from which the uptake behaviour could be deduced. The process was modelled using a 3-dimensional RVE of the material, where di_usion is modelled as steady-state and the di_usivity in each direction was measured by applying concentration gradients to the model. The experimental data shows similar water uptake behaviour for samples in both transverse directions, while the water uptake in the _bre direction was signi_cantly faster. A proper _t according to Fick's law was obtained for the transverse direction, while this was not possible for the samples in _bre direction, suggesting a strong dependency of the di_usion behaviour on the _bre orientation. Results from the proposed numerical models show that the geometric e_ect of _bres acting as barriers for the water movement is indeed responsible for part of the observed anisotropy. @en