Strain-based delamination prediction in fatigue loaded CFRP coupon specimens by deep learning and static loading data

Machine learning (ML) methods for the structural health monitoring (SHM) of composite structures rely on sufficient domain knowledge as they typically demand to extract damage-sensitive features from raw data before training the ML model. In practice, prior knowledge is not available in most cases. Deep learning (DL) methods, on the other...

Effect of interlaying UV-irradiated PEEK fibres on the mechanical, impact and fracture response of aerospace-grade carbon fibre/epoxy composites

Poly-etherether-ketone (PEEK) fibres (average diameter 30μm) were surface-activated by a UV-irradiation technique, and then used as interlayers of carbon fibre/epoxy composites. The results of a flatwise tensile test demonstrated a significant improvement in the PEEK fibre/epoxy adhesion upon the UV-treatment, i.e. the ultimate strength...

On cohesive element parameters and delamination modelling

The cohesive element (CE) has been widely used to model delamination in laminated composites. The penalty stiffness, interfacial strength and fracture toughness are three CE parameters that often determine the accuracy of the numerical analysis by finite elements (FEs). The fracture toughness may be experimentally determined through standard...

Fibre-bridged fatigue delamination in multidirectional composite laminates

The influence of fibre bridging on delamination failure in multidirectional composite laminates with different thickness scales is characterized, and the dependence of fibre bridging significance on laminate thickness as well as loading regime is investigated in this paper. Both quasi-static and fatigue resistance curves (R-curve) are...

Thickness effects on fibre-bridged fatigue delamination growth in composites

This paper provides an investigation on thickness effects on fibre-bridged fatigue delamination growth (FDG) in composite laminates. A modified Paris relation was employed to interpret experimental fatigue data. The results clearly demonstrated that both thickness and fibre bridging had negligible effects on FDG behaviors. Both energy...

Stress ratio dependence of fiber bridging significance in mode I fatigue delamination growth of composite laminates

This paper aims to investigate stress ratio effect on fibre bridging significance in mode I fatigue delamination growth of composite materials. Fatigue resistance curves (R-curves) of different stress ratios are determined and compared with the quasi-static R-curve. The fatigue R-curve of a high stress ratio is similar to the quasi-static...