THE APPLICATION OF OPTICAL FIBRES AS WITNESS DEVICES FOR THE DETECTION OF PLASTIC STRAIN AND CRACKING

Low cost optical fibres have recently become readily available for telecommunications purposes. Silica fibres are characterised by high elastic strains to failure. The feasibility of using these fibres for structural integrity monitoring particularly for off-shore structures is investigated. The basis of the technique is that a fibre may be bonded to a critical part of a structure and provides an optical path which will be broken if the fibre fails due to plastic strain or crack opening in the critical area. Groups of fibres which have been given predetermined fracture strains by surface etching were encapsulated in special packs. These packs were bonded to steel and concrete tensile specimens. Strain transfer occurred successfully between the specimens and individual fibres. The distribution of strain to fibre fracture appeared to be uniform along the fibre. The use of several fibres with a range of fracture strains caused fibres to break progressively with increasing strain. For applications to offshore structures it has been found possible to use water-repellent adhesives which can be applied and cured in sea water and suffer no deterioration. The advantages of this system include versatility, relatively low cost, adaptability to continuous monitoring and the possibility of being fitted retrospectively and refitted after repair operations.(a)

  • Availability:
  • Corporate Authors:

    British Society for Strain Measurements

    281 Heaton Road
    Newcastle-Upon-Tyne, NE6 5QB,   England 
  • Authors:
    • Hale, K F
    • Hockenhull, B S
    • Christodoulou
  • Publication Date: 1980-10

Media Info

  • Features: Figures; Photos;
  • Pagination: p. 150-154
  • Serial:
    • Strain
    • Volume: 16
    • Issue Number: 4
    • Publisher: British Society for Strain Measurements
    • ISSN: 0039-2103

Subject/Index Terms

Filing Info

  • Accession Number: 00329966
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD, TRIS
  • Created Date: Mar 12 1981 12:00AM