• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2025, Vol. 61 ›› Issue (7): 98-108.doi: 10.3901/JME.2025.07.098

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Theoretical Study on the Cutting of CF/PEEK Considering the Elasto-plastic Properties of the Matrix

HU Xiaohang1,2, WANG Fuji1,2, JIA Zhenyuan1,2, JU Pengcheng1,2, WEI Gang1,2, FU Rao1,2   

  1. 1. State Key Laboratory of High-Performance Precision Manufacturing, Dalian University of Technology, Dalian 116024;
    2. Key Laboratory of High-Performance Manufacturing for Advanced Composite Materials, Dalian University of Technology, Dalian 116024
  • Received:2024-07-15 Revised:2024-11-19 Published:2025-05-12

Abstract: Carbon fiber reinforced thermoplastic composites (CFRTP) have garnered significant attention in the high-end equipment manufacturing industry due to their lightweight, high strength, and excellent impact resistance. Compared to traditional carbon fiber reinforced thermoset composites (CFRP), CFRTP have a more plastic matrix, which results in relatively weaker constraints on the fibers during machining. This can lead to greater deformation and increased susceptibility to machining damage. Additionally, the high plasticity of the thermoplastic matrix causes significant differences in material removal behavior and damage form between CFRTP and CFRP during machining. Thus, plasticity is an important and non-negligible characteristic of CFRTP. To accurately describe the effect of the thermoplastic matrix's plasticity on fiber constraint and the cutting process of CFRTP, a cutting mechanics model that considers the elasto-plastic characteristics of the matrix is established. The constraint relationship between the brittle fibers and the high-toughness thermoplastic matrix is characterized using a "spring-St.Venant body" series model. Based on the foundation beam theory and the principle of minimum potential energy, the influence of the matrix's elasto-plastic characteristics on the fiber constraint has been quantitatively analyzed. Finally, taking the typical CFRTP-carbon fiber/polyetheretherketone (CF/PEEK) as the object, the impact of cutting depth on macroscopic cutting forces and subsurface damage is theoretically and experimentally analyzed. The results indicate that the model can accurately predict the macroscopic cutting forces and subsurface damage of CF/PEEK. Within the analyzed range, the model's average prediction errors for cutting force and thrust force are 11.50% and 7.32%, respectively, while the average prediction error for subsurface damage is 2.88%. Compared to algorithm that do not consider the elasto-plastic characteristics of the matrix, the model incorporating the characteristic predicts macroscopic cutting forces more accurately, aligning closer with experimental results.

Key words: CF/PEEK, fiber deformation, elasto-plastic, cutting mechanism, subsurface damage

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