将整个光纤布喇格光栅栅区的非均匀应变简化为多个受到均匀轴向应变光纤光栅基元的级联作用, 仿真分析了锚头典型锚固深度非均匀应变对光纤布喇格光栅输出光谱的影响, 结果表明明常规光纤布喇格光栅无法适用于斜拉索锚头内部轴向非均匀应变测量.为了克服非均匀应变对光纤布喇格光栅应变测量效果的影响, 提出了利用毛细管对光纤布喇格光栅栅区进行应变隔离的新型应变均化传感器结构, 并对传感器的测量原理与力学特性进行分析, 得出毛细管材料与壁厚选型的基本公式.利用碳纤维复合材料作为封装材料, 试制出应变均化FRP-OFBG测力传感器, 并进行了力学拉伸试验.试验结果表明该传感器具有良好的应变传感性能, 且测量量程、刚度满足测量要求.将两只传感器植入试验缆索进行实索张拉试验, 缆索张拉过程中, 同步监测的光纤布喇格光栅输出光谱未受锚头非均匀应变影响, 说明利用毛细管对锚头应变均化的传感器结构方案可行, 且光纤布喇格光栅反射谱中心波长与缆索张力呈较好的线性关系, 说明锚头植入传感器与锚头结合良好, 测力功能满足索力测量需求.

The overall non-uniform gratings were simplified cascading multiple uniform sub-gratings, the effects of three typical non-exponential decays on the output spectrum of Fiber Bragg Grattings(FBGs) were simulated. Simulation results show that the conventional FBG strain sensor is not suitable for anchor axial strain measurement. The structure of FBG strain sensors packaged in thin-walled capillaries was proposed, and the measurement principle and mechanical characteristics were analyzed, the basic formula of capillary material and thickness selection was deduced. The sensor samples were developed with carbon fiber composite materials, and the mechanical tests were carried out. The test results show that the sensors′ performance expectations are achieved. Two FBG strain sensors were pre-implanted into the test anchor, during the tensile process. FBG spectrum occurs no broadening, fission sign, which can meet all the requirements of the prototype cable tests. The relationship between FBG outputs and cable tension are of good consistency, and are of good reproducibility and linearity, which proves that the tension measurement method is entirely feasible.Key words: