开裂条件下塑料光纤的力光转换特性

Optical Response Characteristics of Plastic Optical Fibers Under Cracking Conditions

针对结构出现张开型裂缝条件下塑料光纤的光学感知特性,采用光时域反射技术,分别进行了轴向和非轴向拉伸作用下塑料光纤的力光转换特性试验.结果表明:塑料光纤在受非轴向小角度拉伸时对裂缝感知能力相对更强,当塑料光纤与裂缝呈45°斜交时,光损耗值和菲涅尔反射值的灵敏度分别达到0.87,dB/mm和0.68,dB/mm,且夹角较小时对裂缝的感知灵敏度较高,以塑料光纤内光损耗水平作为裂缝监测指标可监测到的裂缝最大开度为6,mm.可将塑料光纤光损耗量作为结构开裂的监测指标、菲涅尔反射峰作为裂缝发生位置的定位指标,对混凝土工程的裂缝进行监测.

Experiments under axial and non-axial tensions were conducted respectively corresponding to the conditions when opening mode cracks occurred in structures to study the optical response of plastic optical fibers using optical time domain reflect technique.Results indicate that plastic optical fibers have better optical sensibility to cracks under conditions of non-axial strain and small angle.The sensitivities of optical loss and Fresnel reflection are 0.87,dB/mm and 0.68,dB/mm respectively when the angle between the plastic optical fiber and the crack is 45°and the sensitivities are higher when the angle is smaller.It is also shown that the maximum crack width the plastic optical fibers can monitor is 6,mm.Thus plastic optical fibers can be well applied to crack monitoring of concrete structures when taking optical loss as monitoring index and peak of Fresnel reflection as position index.