PSI - Issue 80

ScienceDirect Structural Integrity Procedia 00 (2022) 000 – 000 Structural Integrity Procedia 00 (2022) 000 – 000 Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Available online at www.sciencedirect.com ScienceDirect

www.elsevier.com/locate/procedia www.elsevier.com/locate/procedia

Procedia Structural Integrity 80 (2026) 431–442

© 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Ferri Aliabadi Abstract In recent years, the demand for replacing metal gears with carbon fiber reinforced plastic (CFRP) gears has been increasing due to their high specific strength and excellent vibration damping properties. Conventional fabrication methods include molding short fiber-reinforced resin and machining laminated composites. However, a fabrication method to improve the strength of CFRP gears has not been fully established. In this study, a novel fabrication method was developed to improve the strength of CFRP gears. The proposed method reinforces the tooth flanks with carbon fiber fabrics before casting short fiber-reinforced resin into a mold. To evaluate the effectiveness of this approach, the effects of fiber length, fiber content, and the number of fabric layers on the strength of CFRP gears were investigated. The bending strength of gear teeth was evaluated to verify the practicality of this method. The results indicated that strength improvement requires increasing the fiber volume fraction while ensuring uniform fiber dispersion in the resin. Furthermore, it was found that increasing the number of fabric layers while suppressing interfacial delamination between fibers and resin enhances the strength of the tooth flanks. In conclusion, valuable insights were obtained regarding the applicability of this manufacturing technique for producing high-performance CFRP gears. © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Professor Ferri Aliabadi Keywords: Type your keywords here, separated by semicolons ; 1. Introduction In the current automotive industry, the shift from gasoline vehicles to electric vehicles (EVs) is accelerating. To address the issue of driving range, which is one of the key challenges faced by EVs, the development of EV-specific transmissions is actively underway [Rahman Z. et al. (2000)]. EV motors are typically designed to operate at high speeds of 15,000 rpm to achieve high power density [Aiso K. et al. (2022)], and further increases in rotational speed Fracture, Damage and Structural Health Monitoring Strength Improvement of CFRP Gears by Hybrid Reinforcement Using Carbon Fiber Fabrics and Short Fibers Seiji Mitsubayashi a *, Kenichi Takemura a a Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama, 221-8686, Japan Abstract In recent years, the demand for replacing metal gears with carbon fiber reinforced plastic (CFRP) gears has been increasing due to their high specific strength and excellent vibration damping properties. Conventional fabrication methods include molding short fiber-reinforced resin and machining laminated composites. However, a fabrication method to improve the strength of CFRP gears has not been fully established. In this study, a novel fabrication method was developed to improve the strength of CFRP gears. The proposed method reinforces the tooth flanks with carbon fiber fabrics before casting short fiber-reinforced resin into a mold. To evaluate the effectiveness of this approach, the effects of fiber length, fiber content, and the number of fabric layers on the strength of CFRP gears were investigated. The bending strength of gear teeth was evaluated to verify the practicality of this method. The results indicated that strength improvement requires increasing the fiber volume fraction while ensuring uniform fiber dispersion in the resin. Furthermore, it was found that increasing the number of fabric layers while suppressing interfacial delamination between fibers and resin enhances the strength of the tooth flanks. In conclusion, valuable insights were obtained regarding the applicability of this manufacturing technique for producing high-performance CFRP gears. © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Professor Ferri Aliabadi Keywords: Type your keywords here, separated by semicolons ; 1. Introduction In the current automotive industry, the shift from gasoline vehicles to electric vehicles (EVs) is accelerating. To address the issue of driving range, which is one of the key challenges faced by EVs, the development of EV-specific transmissions is actively underway [Rahman Z. et al. (2000)]. EV motors are typically designed to operate at high speeds of 15,000 rpm to achieve high power density [Aiso K. et al. (2022)], and further increases in rotational speed Fracture, Damage and Structural Health Monitoring Strength Improvement of CFRP Gears by Hybrid Reinforcement Using Carbon Fiber Fabrics and Short Fibers Seiji Mitsubayashi a *, Kenichi Takemura a a Kanagawa University, 3-27-1, Rokkakubashi, Kanagawa-ku, Yokohama, 221-8686, Japan

* Corresponding author. Tel.: +81-45-481-5661; fax: +81-45-481-5661. E-mail address: mitsubayashi@kanagawa-u.ac.jp * Corresponding author. Tel.: +81-45-481-5661; fax: +81-45-481-5661. E-mail address: mitsubayashi@kanagawa-u.ac.jp

2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Professor Ferri Aliabadi 2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Professor Ferri Aliabadi

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of Ferri Aliabadi 10.1016/j.prostr.2026.02.042