Early damage detection in composites by distributed strain and acoustic event monitoring

Neha Chandarana, Daniel Martinez-Sanchez, Constantinos Soutis, Matthieu Gresil

Research output: Chapter in Book/Report/Conference proceedingConference PaperOther

17 Citations (Scopus)


Advances in the development of fibre reinforced polymer composites and their manufacturing techniques have led to their increased use as structural materials. They offer superior corrosion resistance and high specific strength and stiffness, compared to metals, while designing anisotropic structures can provide weight reductions. However, there is uncertainty associated with understanding the consequences of out-of-plane damage in composites. Non-destructive evaluation techniques are adopted in many cases, but represent significant down-time and labour costs. Attached and/or embedded structural health monitoring systems have shown promise in improving the reliability and safety of composites, while reducing lifecycle costs, and improving design and manufacture processes. In this work, a distributed optical fibre sensor is embedded in a six ply carbon fibre-epoxy composite laminate during fabrication, to give three strain sensing regions near the top, middle, and bottom surface of the laminate, which allow in-situ and real time monitoring of strain development in the panel during resin infusion and curing. Four point bending is then conducted on the plate. Acoustic emission events are collected using four bonded piezoelectric wafer active sensors, thus allowing the comparison of strain data with damage formation and growth during progressive loading cycles. Distributed strain data demonstrates the sensitivity of the optical fibre through-the-thickness of the panel. The top, middle, and bottom sensing regions clearly indicate the development of compressive, neutral, and tensile strain, respectively. The strain values obtained from the optical fibre are in good agreement with strain data collected by surface mounted strain gauges. Acoustic event detection suggests the formation of matrix (resin) cracks, with measured damage event amplitudes in agreement with values reported in published literature on the subject.

Original languageEnglish
Title of host publicationProcedia Engineering
Number of pages8
Publication statusPublished - 2017
Externally publishedYes
EventAsia-Pacific Workshop on Structural Health Monitoring 2016 - Hobart, Australia
Duration: 7 Dec 20169 Dec 2016
Conference number: 6th


WorkshopAsia-Pacific Workshop on Structural Health Monitoring 2016
Abbreviated titleAPWSHM 2016


  • Acoustic emission
  • composites
  • distributed strain
  • optical fibre
  • PWAS
  • structural health monitoring

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