TY - JOUR
T1 - On mode-I and mode-II interlaminar crack migration and R-curves in carbon/epoxy laminates with hybrid toughening via core-shell rubber particles and thermoplastic micro-fibre veils
AU - Akbolat, Mehmet Çağatay
AU - Katnam, Kali Babu
AU - Soutis, Constantinos
AU - Potluri, Prasad
AU - Sprenger, Stephan
AU - Taylor, James
N1 - Funding Information:
The authors would like to acknowledge the Ministry of National Education of the Republic of Turkey for the doctoral scholarship offered to Mehmet ?a?atay Akbolat, and also Evonik (Germany) and Technical Fibre Products (UK) for supplying materials.
Publisher Copyright:
© 2022 The Authors
PY - 2022/6/1
Y1 - 2022/6/1
N2 - This study investigates the influence of hybrid toughening—via core-shell rubber (CSR) particles and non-woven thermoplastic veils—on the delamination resistance, crack migration and R-curve behaviour in carbon fibre/epoxy laminates under mode-I and mode-II conditions. Core-shell rubber particles, varying in size from 100 nm to 3 μm, with 0–10 wt% content, are dispersed within the epoxy resin, and thermoplastic micro-fibre veils with polyphenylene sulfide (PPS) fibres, with 5–20 g/m
2 areal weight, are introduced at the interlaminar region to achieve hybrid toughening. Carbon fibre/epoxy laminates are manufactured with a two-part resin using vacuum infusion and out-of-autoclave curing. Double cantilever beam (DCB) and four-point end-notch-flexure (4ENF) specimens are used to obtain mode-I and mode-II fracture energies and R-curves. Damage mechanisms and crack paths are characterised using fractography that provide understanding of energy dissipation. The results show that the hybrid toughening significantly improves fracture initiation and propagation energies (i.e. mode I initiation by ∼245% and propagation by ∼275%, and mode-II initiation by ∼64% and propagation ∼215%) by extrinsic and intrinsic toughening mechanisms. Moreover, it is shown that rising R-curves can be achieved with hybrid toughening when compared with falling R-curves obtained with just thermoplastic veil toughening. Fractography revealed that the hybrid toughening constrained the crack predominantly within the veil region, making it harder to grow and absorb more energy.
AB - This study investigates the influence of hybrid toughening—via core-shell rubber (CSR) particles and non-woven thermoplastic veils—on the delamination resistance, crack migration and R-curve behaviour in carbon fibre/epoxy laminates under mode-I and mode-II conditions. Core-shell rubber particles, varying in size from 100 nm to 3 μm, with 0–10 wt% content, are dispersed within the epoxy resin, and thermoplastic micro-fibre veils with polyphenylene sulfide (PPS) fibres, with 5–20 g/m
2 areal weight, are introduced at the interlaminar region to achieve hybrid toughening. Carbon fibre/epoxy laminates are manufactured with a two-part resin using vacuum infusion and out-of-autoclave curing. Double cantilever beam (DCB) and four-point end-notch-flexure (4ENF) specimens are used to obtain mode-I and mode-II fracture energies and R-curves. Damage mechanisms and crack paths are characterised using fractography that provide understanding of energy dissipation. The results show that the hybrid toughening significantly improves fracture initiation and propagation energies (i.e. mode I initiation by ∼245% and propagation by ∼275%, and mode-II initiation by ∼64% and propagation ∼215%) by extrinsic and intrinsic toughening mechanisms. Moreover, it is shown that rising R-curves can be achieved with hybrid toughening when compared with falling R-curves obtained with just thermoplastic veil toughening. Fractography revealed that the hybrid toughening constrained the crack predominantly within the veil region, making it harder to grow and absorb more energy.
KW - A. Nano-structures
KW - B. Debonding
KW - B. Fracture toughness
KW - D. Fractography
KW - Toughening mechanisms
UR - https://doi.org/10.1016/j.compositesb.2022.109900
U2 - 10.1016/j.compositesb.2022.109900
DO - 10.1016/j.compositesb.2022.109900
M3 - Article
SN - 1879-1069
VL - 238
JO - Composites Part B: Engineering
JF - Composites Part B: Engineering
M1 - 109900
ER -