剪扭作用下塑料光纤力光转换特性试验研究

Experiment of Optical Response Characteristics of Plastic Optical Fibers under Shear and Torsion Loading

为了研究滑开型和撕开型裂缝条件下塑料光纤的光学感知特性,分别进行了剪切和扭转作用下塑料光纤的力光转换特性试验.结果表明,在错动位移由0增加至0.5mm的过程中,光损耗值和菲涅尔反射值与错动位移呈近似线性关系,灵敏度分别达到15.6dB/mm和5.9dB/mm.塑料光纤内部的光损耗特性对剪切作用较敏感,而对扭转作用不敏感,光损耗水平保持在1dB左右.滑开型和撕开型裂缝条件下塑料光纤具有相似的光学感知特性,菲涅尔反射值和光损耗值都可以作为裂缝错动位移的监测指标,其中,光损耗水平变化幅度更大,对裂缝的感知更敏感.

Experiments to study the optical response characteristics of plastic optical fibers under shear and torsion conditions are conducted respectively which are correspond to the conditions when sliding type and tearing type cracks occurred in structures.Results indicate that during the process when the shear displacement increase from 0 to 0.5 mm,the optical loss and Fresnel reflection are linear related to the shear displacement,and the sensitivity of which are 15.6 dB/mm and 5.9 dB/mm respectively,indicating that plastic optical fibers have better optical sensibility to cracks under shear loading conditions,while the sensitivity is low under torsion loading,the optical loss of which is about 1 dB.It can be concluded that plastic optical fibers have the same optical response characteristics when sliding mode or tearing mode cracks occurred in structures.Both Fresnel reflection and optical loss can be used as crack monitoring index among which optical loss is considered to be more sensitive.