09:40
Session 5: Thermoplastic Composites
09:40
20 mins
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Design and Analysis of Thermoplastic Composite Rotor Shafts Manufactured Using Automated Fiber Placement for Electric Motor Applications
Nicole Sharp, Lorenz Zacherl, Farjad Shadmehri
Abstract: The transition toward electrified transportation and energy systems drives the demand for lightweight, efficient, and durable motor components. This study investigates the design for manufacturing and characterization of thermoplastic composite rotor shafts produced by Automated Fiber Placement (AFP) with in-situ consolidation for high-performance electric motor applications. The central research questions address whether AFP-fabricated thermoplastic composites can replace conventional metallic shafts by offering superior strength-to-weight ratio, enhanced performance, and reduced manufacturing costs, while overcoming limitations in interlaminar bonding, void content, and durability.
The methodology follows a multi-stage framework combining numerical modeling, advanced manufacturing, and experimental characterization. First, product and material requirements are defined to guide the selection of carbon and glass fiber-reinforced thermoplastics such as PEEK, PAEK, and PPS, with emphasis on electromagnetic compatibility. Considering the shaft’s rotational nature, the analysis accounts for critical rotordynamic phenomena, including critical speeds, instability regions, and whirling, to ensure proper performance and efficiency. Finite element (FE) analysis is used to optimize layup design, predict residual stresses induced during AFP, and exploit their beneficial contribution to structural performance under high rotational loads. To validate manufacturing strategies, composite rings are fabricated using Concordia University’s AFP facility. The innovative “repass” technique is applied to improve layer bonding without secondary autoclave processing. The effect of this approach is evaluated through short beam shear (SBS) testing, while microscopy is performed to quantify void content and assess bond quality.
It is expected that the results will demonstrate that AFP-fabricated thermoplastic composites provide competitive stiffness and strength compared to autoclave-processed counterparts, while offering significant reductions in manufacturing time and energy consumption. The optimized layup sequences are anticipated to leverage residual stresses to improve shaft stability under centrifugal loading. Furthermore, the “repass” approach is expected to mitigate interlaminar bonding deficiencies and lower void content, leading to improved performance consistency.
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10:00
20 mins
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Experimental and Numerical Study of CF/PEEK Composites in Laser-Assisted Tape Placement with Heated Tool Temperature Above Tg
Hong Ma, Aswani Kumar Bandaru, Paul Weaver
Abstract: The optimisation of process parameters in laser-assisted tape placement (LATP) for CF/PEEK composites has been widely studied; however, controlling the final composite properties remains challenging due to the inherently rapid heating and cooling rates. In this work, a heatable tool was introduced during manufacturing to regulate crystalline morphology and associated properties by maintaining the tool temperature within the crystallisation range of the matrix. Raising the tool temperature to 200 °C increased the average spherulite size from ~1.5 µm to ~3.2 µm and the crystallinity from 34% to 37%. Numerical simulations revealed that in conventional LATP (without a heated tool), the tape surface temperature decreases rapidly from ~320 °C at the nip point to ~220 °C upon exiting compaction by the roller. By contrast, with a tool temperature of 200 °C, the temperature drop was limited to ~320 °C to ~285 °C, arising from the significantly reduced the temperature difference between the incoming tape and substrate before nip point. This enhanced thermal profile promoted polymer diffusion, reduced interlaminar void content, and improved crystallisation. Transmission electron microscopy further confirmed the formation of a distinct diffusion region at tool temperatures above Tg, characterised by intermediate oxygen and carbon concentrations between fibre and matrix. These microstructural changes in crystalline morphology, void distribution, and interfacial structure were found to strongly influence the mechanical performance, including interlaminar shear strength and fracture toughness of CF/PEEK composites. Such findings are expected to provide new insights into optimising the performance of CF/PEEK composites manufactured by LATP through controlled microstructure, by introducing additional energy sources to address the intrinsic rapid heating and cooling rates without requiring major modifications to the LATP process.
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