Monitoring of Carbon Fiber-Reinforced Old Timber Beams via Strain and Multiresonant Acoustic Emission Sensors

Francisco J Rescalvo; Ignacio Valverde-Palacios; Elisabet Suarez; Andrés Roldán; Antolino Gallego

doi:10.3390/s18041224

Monitoring of Carbon Fiber-Reinforced Old Timber Beams via Strain and Multiresonant Acoustic Emission Sensors

Sensors (Basel). 2018 Apr 17;18(4):1224. doi: 10.3390/s18041224.

Authors

Francisco J Rescalvo¹, Ignacio Valverde-Palacios², Elisabet Suarez³, Andrés Roldán⁴, Antolino Gallego⁵

Affiliations

¹ Department of Applied Physics, University of Granada, Campus Fuentenueva s/n, 18071 Granada, Spain. rescalvo@ugr.es.
² Department of Building Constructions, University of Granada, Campus Fuentenueva s/n, 18071 Granada, Spain. nachoval@ugr.es.
³ Department of Applied Physics, University of Granada, Campus Fuentenueva s/n, 18071 Granada, Spain. elisabetsv@ugr.es.
⁴ Department of Electronics and Computer Technology, University of Granada, Campus Fuentenueva s/n, 18071 Granada, Spain. amroldan@ugr.es.
⁵ Department of Applied Physics, University of Granada, Campus Fuentenueva s/n, 18071 Granada, Spain. antolino@ugr.es.

Abstract

This paper proposes the monitoring of old timber beams with natural defects (knots, grain deviations, fissures and wanes), reinforced using carbon composite materials (CFRP). Reinforcement consisted of the combination of a CFRP laminate strip and a carbon fabric discontinuously wrapping the timber element. Monitoring considered the use and comparison of two types of sensors: strain gauges and multi-resonant acoustic emission (AE) sensors. Results demonstrate that: (1) the mechanical behavior of the beams can be considerably improved by means of the use of CFRP (160% in bending load capacity and 90% in stiffness); (2) Acoustic emission sensors provide comparable information to strain gauges. This fact points to the great potential of AE techniques for in-service damage assessment in real wood structures.

Keywords: acoustic emission sensors; carbon fiber composites; structural monitoring; timber.