Thermoplastic–epoxy interactions and their potential applications in joining composite structures – A review Part A Applied science and manufacturing

Tensile failure of laminates containing an embedded wrinkle; numerical and experimental study Part A Applied science and manufacturing

https://purehost.bath.ac.uk/ws/files/188569936/pdf_archiveAPPLABvol_113iss_24243704_1_am.pdf

Stacking sequence selection for defect-free forming of uni-directional ply laminates

The effect of inter-ply sliding was investigated for multi-ply Non-Crimp Fabric (NCF) preforms during the Double Diaphragm Forming (DDF) process. A Finite Element (FE) model was employed to investigate the influence of the ply layup sequence and the coefficient of friction between fabric-fabric and fabric-diaphragm interfaces. Simulation results indicate that in-plane fibre compression, caused by dissimilar shear deformation between adjacent plies, can lead to out-of-plane wrinkles, where the wrinkle length is a function of the relative fibre angle at the ply-ply contact interface. The most severe wrinkles occurred when the inter-ply angle was 45° for a multi-ply biaxial NCF preform with a pillar stitch at 45° to the primary yarns. A second parametric study was conducted by incrementally reducing the coefficient of friction at the ply-ply interface. Experiments confirmed that out-of-plane wrinkles are sensitive to the friction resistance between NCF plies and therefore lubricating the fibres can minimise wrinkling defects caused by dissimilar inter-ply deformation.

Investigation into the effects of inter-ply sliding during double diaphragm forming for multi-layered biaxial non-crimp fabrics

The effects of the toughening mechanism and the molecular weights between cross-links on the fatigue resistance of epoxy polymer blends

Interleaving a laminated composite with thermoplastic particles is known as an effective method to improve the interlaminar fracture toughness. In this work, to provide useful insight into what particle characteristics are the most critical to the toughening effect, the interlaminar fracture behaviours of carbon fibre/epoxy composites interleaved with different types of nylon 6 and 12 particles were investigated in the same range of particle areal weights. The results showed the particle size affects the toughness only when the particle–matrix interfacial bonding is well established, which is related to the curing temperature relative to the melting temperature of the particle. High interfacial bonding strength allowed the particles to be plastically deformed while bridging the crack, and smaller particles were more effective due to the increased density of particle bridging. It was also found that both the particle size and shape affect thickening of the interlayer, which can cause a knockdown of in-plane laminate properties due to the reduced fibre volume fraction.

/pdf/effect-of-the-characteristics-of-nylon-microparticles-on-3l9g0ldsgz.pdf

Effect of the characteristics of nylon microparticles on Mode-I interlaminar fracture toughness of carbon-fibre/epoxy composites

/pdf/improvement-of-composite-drape-forming-quality-by-enhancing-2nu4oxi7qk.pdf

Improvement of Composite Drape Forming Quality by Enhancing Interply Slip

Toughening epoxy based composite materials using thermoplastic particles is a cost-effective approach to improve their poor delamination resistance. In this paper, the interlaminar toughening effect of different thermoplastic microparticles such as polyamide-6 and polyamide-12 particles for a carbon fibre/epoxy composite was investigated. The particles with a range of different areal weights were directly deposited on the prepreg surface to toughen the interlaminar region of the cured laminate samples. From the scanning electron microscope (SEM) observations, it was found that the effects of the three thermoplastic particles on the interlaminar fracture behaviour were different. It was also found that the particle areal weight affected the Mode-I fracture toughness differently depending on the particle material. In some cases, no toughening effect was observed.

/pdf/the-interlaminar-fracture-toughness-of-carbon-epoxy-28sav1o5aq.pdf

Wei-Ting Wang

Papers

Effect of the characteristics of nylon microparticles on Mode-I interlaminar fracture toughness of carbon-fibre/epoxy composites

Improvement of Composite Drape Forming Quality by Enhancing Interply Slip

The Interlaminar Fracture Toughness of Carbon/Epoxy Laminates Interleaved with Polyamide Particle Layers

“Un-forming” fibre-steered preforms: Towards fast and reliable production of complex composites parts

Virtual Un-manufacturing of Fibre-steered Preforms for Complex Geometry Composites