Strain, natural frequency, damping coefficient and elastic modulus of mortar beams determined by fiber Bragg grating (FBG) sensors

Deformação específica, frequência natural, coeficiente de amortecimento e módulo elástico de vigas de argamassa determinados por sensores em fibra ótica com rede de Bragg (FBG)

Abstract

Structural health monitoring can detect anomalies in time, allowing the implementation of more efficient maintenance and repair actions in special engineering structures. An alternative in the monitoring and evaluation of structures in civil engineering is the use of optical fibers inscribed with Bragg gratings (FBG or Fiber Bragg Grating). This paper aims to compare available techniques to estimate the elastic module of cementitious composites, as well as contribute to the application of optical fiber sensors in the monitoring of strain, natural vibration frequency, damping coefficient and elastic modulus of mortar beams. The FBG sensors manufactured and calibrated by the authors presented a good precision for measuring those parameters in mortar samples. The results show that FBG sensors and strain gauge sensors present a similar result for strain and estimation of the elastic module (static and dynamic), therefore, bare FBGs could be further investigated for non-destructive testing.

Keywords:
modulus of elasticity; structural analysis; impulse excitation of vibration; non-destructive testing; optical fiber sensors