de Vega, E.S., Allegri, G., Zhang, B. orcid.org/0000-0002-0428-7745 et al. (2 more authors) (2022) Improving the delamination bridging performance of Z-pins through the use of a ductile matrix. Composites Part A: Applied Science and Manufacturing, 163. 107241. ISSN 1359-835X
Abstract
This paper presents a characterisation of the effect of varying the polymer matrix in Z-pin through-thickness reinforcement in pre-preg based laminates. Four matrix systems of increasing elongation at break are considered, namely: 1) a low glass-transition temperature (LTG) epoxy; 2) a high glass-transition temperature (HTG) epoxy; 3) a bismaleimide triazine (BT); 4) a bismaleimide (BMI). The last matrix is that used in commercially available Z-pins. The manufacturing of T300 carbon-fibre Z-pins employing the first three matrices via micro-pultrusion is discussed. The BT resin is considered as a benchmark for the manufacturing process. A preliminary screening of the mode II bridging performance of through-thickness reinforcement manufactured using the three matrix systems is carried out. A novel experimental set-up based on an acrylic glass carrier, which allows the failure mode of the through-thickness reinforcement to be visualised, is introduced. The preliminary tests reveal a 7-fold increase of work-to-failure for the candidates with the highest elongation at break, LTG Z-pins, compared to their baseline BMI-based counterparts. LTG Z-pins were then inserted in quasi-isotropic E-glass epoxy laminates and their bridging performance characterised across the full mode-mixity range. The experimental results indicate that LTG Z-pins provide a peak mode I interlaminar fracture toughness of the order of 40 kJ/m2, compared to the 28 kJ/m2 yielded by BMI Z-pins. Moreover, the transition from full pull-out to rupture for the LTG pins occurs at a mode-mixity of 0.55, whereas BMI Z-pins start failing at a mode-mixity of 0.2. The superior bridging performance of the LTG Z-pins is correlated with the enhanced ductility and toughness of the constituent matrix via detailed fractographic observations.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2022 The Authors. This is an open access article under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. |
Keywords: | A. Polymer-matrix composites (PMCs); B. Delamination; E. Pultrusion; Z-pins |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mechanical Engineering (Leeds) > Institute of Engineering Systems and Design (iESD) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 03 Oct 2024 13:36 |
Last Modified: | 03 Oct 2024 13:36 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.compositesa.2022.107241 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:217861 |