Deformation reconstruction of a smart Geogrid embedded with fiber Bragg grating sensors
Deformation reconstruction of a smart Geogrid embedded with fiber Bragg grating sensors
复制标题
嵌入光纤布拉格光栅传感器的智能土工格栅的变形重建
DOI：
10.1088/0957-0233/26/12/125202
复制
发表时间：
2015-12-01
影响因子：
2.4
通讯作者：
Lu, Shi-de
中科院分区：
文献类型：
--
作者：
Wang, Zheng-fang;Wang, Jing;Lu, Shi-de
针对目前智能土工格栅只能测量应变和评估荷载位置的缺点，研制了一种内嵌光纤光栅（FBG）传感器的智能土工格栅。此外，变形重建技术进行了研究，这使得新设计的智能土工格栅，以评估在岩土结构的关键区域的变形场。在简要介绍了光纤光栅嵌入式智能土工格栅的制作过程后，详细介绍了一种基于曲率信息的智能土工格栅变形重构方法。为了优化智能土工格栅中FBG节点的分布，提取了3种可能引起变形的有限元模拟数据，并对4种分布的重构结果进行了比较。结果表明，光纤光栅传感器等间距分布在智能土工格栅的肋是新设计的智能土工格栅的最佳分布。此外，提出了一种改进的变形重建技术，以减少由于应力集中的智能土工格栅的连接处的重建误差。通过有限元仿真验证了该方法的有效性。仿真结果表明，无论是单根光缆嵌入同一经线的土工格栅，还是多根光缆嵌入不同经线的土工格栅，改进后的方法都能提高变形重构精度。为了验证所设计的智能土工格栅的变形测量的可行性，使用所提出的重建技术，实验的智能土工格栅嵌入一个光纤电缆在恒温环境中进行。为了消除应变测量引起的误差，在变形试验前对智能土工格栅的曲率进行了标定。实验结果表明，新设计的智能土工格栅的重构技术能够对变形场进行评估，改进后的重构技术能够有效提高重构精度，满足土工工程应用的要求。新开发的智能土工格栅与变形重建技术可以是一个有前途的智能土工合成材料的加固以及监测岩土工程相关的应用。
Due to the disadvantages of the current smart Geogrid for geotechnical use only being able measure strain and evaluate load location, a smart Geogrid embedded with fiber Bragg grating (FBG) sensors has been developed. Also, a deformation reconstruction technique has been investigated, which enables the newly designed smart Geogrid to evaluate the deformation fields of the key areas in geotechnical structures. After the fabricating process of the FBG embedded smart Geogrid was briefly introduced, a curvature information based deformation reconstruction method for the smart Geogrid was detailed. In order to optimize the distribution of the FBG nodes in the smart Geogrid, the finite element (FE) simulation data of the three possible causes of deformation were extracted, and the reconstruction results of the four distributions were compared. The results indicated that equidistantly distributed FBG sensors at the ribs of the smart Geogrid were the optimal distribution for the newly designed smart Geogrid. In addition, a modified deformation reconstruction technique was proposed to reduce reconstruction errors due to the stress concentration on the junctions of the smart Geogrid. The modified method, which employs FBG measured strains for calculating the deformation of the ribs and weighted strains to compute the coordinates of the two junctions, was validated by FE simulations. The simulation results illustrated that the modified method can improve the deformation reconstruction accuracy for both a Geogrid embedded with one fiber optic cable into one warp thread and a Geogrid embedded with multiple fiber optic cables in different warp threads. For the purpose of verifying the feasibility of the deformation measurements for the designed smart Geogrid using the proposed reconstruction techniques, experiments for the smart Geogrid embedded with one fiber optic cable were conducted in constant temperature environments. The curvatures of the smart Geogrid were calibrated prior to the deformation experiments in order to remove the errors induced by the strain measurement. The experimental results demonstrated that the reconstruction technique for the newly designed smart Geogrid was capable of evaluating the deformation field, and the modified reconstruction technique was able to effectively improve the reconstruction accuracy in order to fulfill the requirements of geotechnical usages. The newly developed smart Geogrid with deformation reconstruction techniques can be a promising smart Geosynthetic for the reinforcement as well as the monitoring of geotechnical engineering-related applications.