Monitoring of Non-Homogeneous Strains in Wood Glued Joints with Embedded FBG Optical Sensors in Mode I Delamination Tests

• Type: Article in International Conference Proceedings Book
• Date: 2013

Authors

Maciel, RS (Author) Other; Frazao, O (Author) FCUP; Morais, JJL (Author) Other; Fernandes, JRA (Author) Other

Conference proceedings International

Title: 8TH IBEROAMERICAN OPTICS MEETING AND 11TH LATIN AMERICAN MEETING ON OPTICS, LASERS, AND APPLICATIONS

8th Iberoamerican Optics Meeting and 11th Latin American Meeting on Optics, Lasers, and Applications

Porto, PORTUGAL, JUL 22-26, 2013

Indexing

ISI Web of Knowledge - 2 Citations

Scopus - 3 Citations

Other information

Authenticus ID: P-006-K4N

DOI: 10.1117/12.2031893

Abstract (EN): In this work it is presented a study of the reflection spectra yielded by a Fiber Bragg Grating sensor embedded into an epoxy glue line between two wood arms, in a double cantilever beam (DCB) Mode I delamination test. The reflection spectra were obtained using a Spectral Analyzer Fibersensing Bragmeter FS2200SA in regular time intervals, as the stress applied to the laminates is continuously increased until fracture occurs. They initially show a typical Bragg grating reflection spectrum, which gradually changes into more complicated, multiple-peak spectra, resulting from a non-homogenous strain distribution along the board line. Based on these results, a model was derived for the variation of the grating effective index which fits the observed spectra when the irregular strain distribution is observed. This model consists of usual cosine description of Bragg grating effective index with linear phase variation, plus a logarithmic phase change along the fiber length, resulting in the increment of the grating wavelength with increasing distance from the load application point. Moreover, from this model the strain distribution along the grating is found, yielding the expected result.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 5