基于光纤Bragg光栅的缆索和索端锚头应力测量方法

Stress Measurement at Cable and Anchor End by Using Fiber Bragg Grating

为了防止缆索护栏由于索端锚头或缆索松动而不能起到应有的保护作用,采用一种基于光纤Bragg光栅非电量测量方法对其所受应力进行测量。将光纤Bragg光栅分别布设于缆索护栏的索端锚头刻槽内和缆索钢丝表面,通过破坏性拉伸试验与压力试验,得到应力与光纤Bragg光栅中心波长移位的数学关系。结果表明:拉伸时索端锚头处光纤Bragg光栅灵敏度为2×10-6μm.kN-1,缆索处光纤Bragg光栅灵敏度为6×10-6μm.kN-1;受压时索端锚头处光纤Bragg光栅传感器灵敏度为4×10-6μm.kN-1;光纤Bragg光栅传感器的测量量程和测量精度均能满足对缆索护栏监测的要求。

In order to guarantee the original protection of the cable guardrail in the cases of cable loose or anchor end loose, a non-electricity method based on fiber Bragg grating （FBG） was used to measure the stress. FBGs were bond in the slot of the anchor end and on the surface of a single wire of the cable, and the relationship between the FBG wavelength shifts and stress could be got through the destructive tensile and pressure tests. The results indicate that the response sensitivity of FBGin the anchor end is 2×10-6μm.kN-1, and on the cable is 6 μm.kN-1 in tensile test; the sensitivity of FBG in the anchor end is 4×10-6μm.kN-1 in pressure test; and FBG sensor measuring range and measuring precision can meet the requirements of the cable guardrail monitoring.