The effect of semi‑cured elements on the quality of integrated composite structures

Arjun Radhakrishnan*, Mark Mavrogordato, Petar Zivkovic, Turlough McMahon, James Kratz*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

There is a demand to ramp up the rate of production of primary aerostructures and as such new processing methods are required. This study investigates a two-stage process for integrating composite structures. In Stage 1, a series of doublers are infused and semi-cured to a target degree of cure (α). In Stage 2, these doublers are integrated into a preformed stiffened panel, to increase thickness locally, followed by infusion. The impact of this integration on quality in terms of thickness and void content of the semi-cured doublers is assessed through the processing stages. The results indicate that semi-curing elements to a higher degree of cure (α = 0.74) around the gel point (α = 0.70) of the epoxy matrix have minimal impact on the relative quality of the final structure. However, at a lower semi-cure (α = 0.47), the void (> 100 µm) content increased from 0.8 to 1.92% during the secondary stage. Tracking the thermal profile of the semi-cured elements through the stages combined with a Cure-Temperature-Transition diagram shows that at a lower degree of cure, the resin in the semi-cured doublers will be in a liquid phase during Stage 2 leading to the potential for resin reflow.
Original languageEnglish
Pages (from-to)2757-2768
Number of pages12
JournalInternational Journal of Advanced Manufacturing Technology
Volume136
Issue number5
Early online date14 Jan 2025
DOIs
Publication statusE-pub ahead of print - 14 Jan 2025

Bibliographical note

Publisher Copyright:
© The Author(s) 2025.

Keywords

  • Parital curing
  • Composite structures
  • Aerostructures
  • Staged-curing
  • Modified Co-curing
  • Integrated structures
  • Composite Joining
  • High-rate manufacturing

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  • Layer by Layer Curing

    Kratz, J. (Principal Investigator)

    1/06/2030/11/23

    Project: Research

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