Effect of residual strain on sensing property of FRP-OFBG smart rebar

摘要

FRP-OFBG smart rebar is the smart structure material, which is the integration of good mechanical property and sensing performance. And FRP-OFBG rebar can be widely used in civil engineering health monitoring. But in the smart rebar application procedure, there is large residual strain exiting in FBG in smart rebar, and multiple-peaked to FBG reflection spectrum, which affect the sensing performance of smart rebar. In this paper, it's theoretically analyzed using FBG to measure the residual strain in FRP after fabrication; In smart rebar pultrusion fabrication processing, the strain and temperature were monitored by two connecting FBGs. It's analyzed FRP fabrication processing through monitoring data; To the multiple-peaked smart rebar, which caused by nonuniform residual strain distributing along FBG length, post thermal treatment was done. The result proved that thermal treatment can improve the spectrum of smart rebar and remove the multiple-peaked phenomenon of smart rebar. But the thermal treatment can't relief the residual strain, and further research about how long will the residual strain recovery at room temperature must be done.