Hole making performance and damage mechanisms of carbon fibre reinforced polyetherketoneketone (CF/PEKK)

  • Jia Ge

Student thesis: Doctoral Thesis › Doctor of Philosophy

Abstract

Recently, carbon fibre reinforced thermoplastic composites (CFRPTs) have received increasing interest in various industries, particularly in aerospace, due to their good recyclability/reparability and high production turnover. Carbon-fibre-reinforced-polyetherketoneketone (CF/PEKK) stands out as a highly promising CFRTP material due to its outstanding mechanical properties/thermal stability. Creating high-quality holes in CF/PEKK for aircraft assembly through riveting remains a challenge due to the material’s heterogeneous structure and thermal sensitivity. To date, the hole making performance and damage mechanisms of CFRTPs, particularly CF/PEKK, remain a significant but understudied area.

In this work, the hole making performance of CF/PEKK has been investigated for the first time. The impact of different hole making conditions (conventional drilling and helical milling) and effects of drilling parameters (feed rate, spindle speed) on the resulting thrust force, temperature and chip morphology, hole delamination/microstructural damage and material removal mechanisms, have been thoroughly investigated and wherever possible, compared with that of the conventional CF/epoxy. Multi-objective optimization has been conducted to identify the optimal drilling parameters for CF/PEKK. In addition, temperature controlled orthogonal cutting was carried out to reveal the fundamental temperature-dependent cutting physics of CF/PEKK.

This PhD project has created a significant body of new knowledge in relation to CFRTPs machining process and the associated cutting physics, which is expected to provide important guidance for low-damage, high-efficiency machining of CFRTPs.

Thesis is embargoed until 31 July 2026.
Date of AwardJul 2023
Original languageEnglish
Awarding Institution
  • Queen's University Belfast
SponsorsUK Research and Innovation
SupervisorDan Sun (Supervisor), Yan Jin (Supervisor) & Giuseppe Catalanotti (Supervisor)

Keywords

  • CFRTP
  • CF/PEKK
  • Drilling
  • Machining
  • Damage mechanism
  • Thermoplastic composites

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