一种基于光纤布拉格光栅的金属腐蚀传感器

基于钢筋混凝土中钢筋锈蚀膨胀和光纤布拉格光 栅(FBG)应变测量原理,设计了一种新型的FBG金属腐蚀传感器。传感器由FBG腐蚀测量传 感器、FBG温度补偿传感器和带有通槽、凹槽、 通孔的钢筋件组成。FBG腐蚀测量传感器用于测量钢筋锈蚀引起的应变,FBG温度补偿传感器 用于消除温 度交叉敏感特性。钢筋件的通槽用环氧树脂填充后,把腐蚀测量传感器的FBG紧密缠绕在钢 筋件的表面, 并固定在环氧树脂固定点上。温度补偿传感器的FBG经过增敏处理后布置在通孔中。推导了 钢筋锈蚀率与FBG波长的理论计算公式；制作了用水泥砂浆封装的FBG金属 腐蚀传感器；最后在制作的混凝土试件上进行加速腐蚀实验,考核传感器的性能。实验结果 表明,设计的FBG 金属腐蚀传感器能够直接测量钢筋的锈蚀程度,并且具有较大的量程,可实现钢筋 混凝土结构中钢筋的 轻微锈蚀和较严重锈蚀情况监测,适用于建筑、桥梁和隧道等领域钢筋混凝土结构中钢 筋锈蚀的结构健康监测。

Research on a fiber Bragg grating based corrosion sensor

The fiber Bragg grating (FBG) wavelength shift in an FBG strain sensor which is caused by expansive rebar corrosion products will be detected and monitored by an FBG interrogator. Based on this principle,a new type of FBG corrosion sensor is proposed in this paper,which consists of an FBG corrosion measurement sensor, an FBG temperature compensation sensor,and a customized rebar which has a pair of radial grooves,a pair of axial grooves,and a through-hole located between the two axial grooves.The FB G corrosion measurement sensor is designed to measure the expansion strain caused by rebar corrosion,and the F BG temperature compensation sensor is designed to eliminate the cross-sensitivity of FBG corrosion measurem ent sensor.The customized rebar with radial epoxy fixing grooves is designed to install the FBG corrosion measur ement sensor on its surface and the sensitivity enhanced FBG temperature compensation sensor in the through-hol e which is finally connected with optical cable in axial grooves.The corrosion rate is derived by the wavele ngth shift of FBG corrosion sensor in this paper,so the rebar corrosion can be monitored and assessed by the FBG wavel ength shift.The FBG corrosion sensor is embedded in cement mortar and subsequently casted in concrete.The per formance of the FBG corrosion sensor is studied in an accelerated electrochemical corrosion test.Ex perimental results show that the new type of FBG corrosion sensor has relatively large measurement r ange of corrosion rate.The FBG corrosion sensor is suitable for monitoring slightly and moderately corroded reb ars,thus the FBG corrosion sensor can be employed to monitor the rebars in reinforced concrete structures,such as buildings,bridges and tunnels.