介绍了光纤传感涉及的应变传递理论, 基于该理论建立了基体和感知光纤应变的定量关系, 以消除应变传递误差, 提高测试精度。针对埋入式光纤传感器用于高黏度的柔性沥青路面基体的最普遍形态, 建立了含感知光纤、封装层和基体的典型三层力学模型。采用Goodman假设描述层间剪应力关系, 引入傅里叶级数法求解微分方程, 建立了基体和感知光纤的平均应变传递关系。通过室内试验论证了推导的应变传递理论公式的有效性, 并对影响平均应变传递效率的几何参数和材料参数进行了灵敏度分析。分析结果表明: 光纤粘贴长度越长, 光纤和封装层的层间黏结越紧密, 平均应变传递系数越大, 应变传递效果越好。本文的研究可广泛用于埋入式光纤传感器的应变传递误差修正及封装设计。

Strain transfer theory for optical fiber sensing was introduced, and the quantitative relationship of strains between host material and optical fiber was set up to eliminate the strain transfer errors and to improve the testing precision on the basis of the strain transfer theory. A typical three-layered structural model containing a sensing optical fiber, a package layer and a host was established for the application of an optical fiber sensor embedded in asphalt pavement. The Goodmans hypothesis was introduced to describe the relationship of interfacial shear stresses between layers, and the Fourier series was adopted to solve the differential equation and to establish the average strain transfer relationship between host material and optical fiber. The effectiveness of the formula of strain transfer theory derived by this paper was validated experimentally. Moreover, the sensitivity of related geometrical and physical parameters effecting on the average strain transfer efficiency was discussed. The analytical results indicate that average strain transfer coefficient increases with the growth of sensing length and the interfacial adhesion coefficient between optical fiber and protective layer. The work in this paper could be widely used for the modification of strain transfer errors and the design of embedded optical fiber sensors.