应力传感光缆的应力传递特性

Stress transfer performance of strain sensing cable

光纤应力传感系统通常采用传感光缆代替裸光纤作敏感元件,因此研究传感光缆应力传递性能很有必要。本文从弹性力学的角度,利用拉梅公式和广义胡克定律相结合的方法,为紧缚型传感光缆和加强型传感光缆建立了应力传递理论模型,推导出光缆的应变与它受到的应力之间的关系。分别对紧缚型和加强型传感光缆的样品进行了应力实验,利用布里渊光学时域反射仪(BOTDR)测量了光缆的应变。结果显示,理论计算和实验测量的趋势一致,线性度均超过了97%,斜率之间的差别小于8%,从而证明了理论模型的有效性。该模型可为光纤应力传感系统判定被测对象受力状况提供直接依据。

In a fiber strain sensing system,strain sensing cable is usually used as a sensing element instead of bare fiber.Therefore,it is necessary to explore the high stress transfer performance of a strain sensing cable.Combining Lame formula and generalized Hooke＇s law,this paper establishes theoretical models for a tight-jacketed sensing cable and a reinforced sensing cable based on elasticity mechanics and deduces the relationship between the strain of the cable and its stress. Then it does the simulation and experiment on samples of these two typical types of sensing cables by using Brillouir Optical Time-domain Reflectometer（BOTDR） to detect the strain of the cables.The results of theoretical calculation and the experimental measurement show that the linear rates of all the results are more than 97%,and the differences of the slope between the theoretical calculation and the experimental measurement are less than 8%,which proves the models to be effective.The models can provide a basis for stress sensing systems in determining the stress situation for an objective.