Acousto-ultrasonic sensing for delaminated GFRP composites using an embedded FBG sensor

Pou Man Lam, Kin Tak Lau, Hang Yin Ling, Zhongqing Su, Hwa Yaw Tam

Research output: Journal article publicationJournal articleAcademic researchpeer-review

54 Citations (Scopus)


In this paper, an active damage detection system for composite laminates is introduced. A fiber Bragg grating (FBG) was employed as an embedded sensor for detecting ultrasonic Lamb wave generated by a piezoelectric (PZT) actuator, inside the laminates. There were two different configurations for the system, making use of a broadband light source and a laser source, respectively. It was found that the use of a laser source could provide a higher sensitivity, so it was preferred in an ultrasonic signal acquisition unit for damage detection. When a delamination is developed in composite structures, the propagation characteristics of Lamb wave is then changed. According to altered signals, the types and natures of delamination inside the structures can be evaluated. In this experiment, glass fiber-reinforced epoxy (GFRP) composite beams were used to study the feasibility of our proposed detection technique. FBG sensors were embedded in different layers of the composite beams. The responses of FBG sensors from both intact and delaminated composite beams were then compared. Finally, the acquired Lamb wave signals corresponding to different delamination sizes and locations were examined.
Original languageEnglish
Pages (from-to)1049-1055
Number of pages7
JournalOptics and Lasers in Engineering
Issue number10
Publication statusPublished - 1 Oct 2009


  • Composite structures
  • Damage detection
  • Delamination
  • Fiber Bragg grating (FBG)
  • Lamb wave

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering
  • Atomic and Molecular Physics, and Optics
  • Mechanical Engineering

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