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The effect of ply drop-off on tensile strength of thermoplastic carbon fiber composite: a numerical and experimental study

Daouda Kane (Mechanical Engineering Institute, Universidade Federal de Itajuba, Itajuba, Brazil)
Guilherme Gomes (Mechanical Engineering Institute, Universidade Federal de Itajuba, Itajuba, Brazil)
Vanessa Macanhan (LNA, Itajuba, Brazil)
Antonio Ancelotti Jr (Mechanical Engineering Institute, Universidade Federal de Itajuba, Itajuba, Brazil)

Engineering Computations

ISSN: 0264-4401

Article publication date: 31 March 2022

Issue publication date: 7 June 2022

122

Abstract

Purpose

In laminate composite structure design, it is common to deal with the need of varying thickness to reach project requirement or improve performance. This change of thickness can be achieved by terminating or adding plies at different locations over the laminate. Unfortunately, the inherent weakness of this construction is the presence of material and geometric discontinuities at the ply drop region that induce premature interlaminar failure at interfaces between dropped and continuous plies.

Design/methodology/approach

In this work, tensile strength tests were performed on tapered laminates with internal ply drop-off using digital image correlation (DIC) technique. The laminate based on a new thermoplastic ELIUM® 150 reinforced by a plain weave carbon fabric was manufactured via VARTM. Stress, strain, displacement and tensile strength were analyzed. A 3D finite element analysis (FEA) and design of experiments (DOEs) were carried out for the analysis of effect of position and angle orientation of dropped plies near the thinner section of the tapered laminate. Tsai Wu's criterion was implemented to predict initiation of first ply failure.

Findings

Numerical and experimental results showed that position and angle orientation of ply drop-off near the thinner thickness influence tensile strength of tapered laminate. Tensile static strength increases 12% when drop-off near the midplane is oriented at ±45° instead of 0°. Results showed a trend of improvement in the tensile strength when drop-off is positioned over midplane of the laminate composite. Results obtained through the DOEs were able to adjust the metamodel according to a linear model with great efficiency. They show the significant relevance of the manufacturing variables and the interaction between the factors.

Originality/value

The present work aims to evaluate the effect of ply drop-off on the strength of carbon fiber thermoplastic composite laminates with internal drop-off under tensile load and propose a design guideline about angle orientation and position of dropped plies closer to the thinner section of the laminate.

Keywords

Acknowledgements

The authors would like to acknowledge the financial support from the Brazilian agency CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico – grant 431219/2018-4 and 311709/2017-6) and FAPEMIG (Fundação de Amparo à Pesquisa do Estado de Minas Gerais – grant APQ-00385-18).

Funding: This study was funded by agency CNPq (Conselho Nacional de Desenvolvimento Científico e Tecnológico – grant 431219/2018-4 and 311709/2017-6) and FAPEMIG (Fundação de Amparo à Pesquisa do Estado de Minas Gerais – grant APQ-00385-18).

Ethical approval: The article follows the guidelines of the Committee on Publication Ethics (COPE) and involves no studies on human or animal subjects.

Consent to participate: Not applicable. The article involves no studies on humans.

Consent to publish: Not applicable. The article involves no studies on humans.

Authors’ contributions: Kane developed the entire methodological study and part of the results. Gomes, Ancelotti Jr and Macachan contributed with investigations, design of experiments and results discussion. All authors read and approved the final manuscript.

Availability of data and materials: The authors confirm that material supporting the findings of this work is available within the article. The collected data of this work are not available within the article.

Conflict of interests: The authors declare that they have no conflict of interest.

Citation

Kane, D., Gomes, G., Macanhan, V. and Ancelotti Jr, A. (2022), "The effect of ply drop-off on tensile strength of thermoplastic carbon fiber composite: a numerical and experimental study", Engineering Computations, Vol. 39 No. 6, pp. 2284-2305. https://doi.org/10.1108/EC-07-2021-0383

Publisher

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Emerald Publishing Limited

Copyright © 2022, Emerald Publishing Limited

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