基于iBeam3单元逆有限元法的冻土区管道变形研究

形状传感技术结合了应变-形状算法，使测点的应变与空间位置对应。该技术能真实地反映待测物的空间姿态与形状变化，可实现动态实时监测。该文提出了一种基于iBeam3单元的逆有限元法来实现管道变形状况的实时监测。建立了基于iBeam3单元的逆有限元法的理论框架模型；试验验证了其合理性；设计了冻土区管道变形试验，结合应变传感器所测表面应变信息建立逆有限元分析模型；实现了在整个冻融循环过程中对管道形状的重建。试验结果表明:该方法不仅能实时监测管道随土体冻融循环的完整变形过程，而且可以保证精度。在解决寒区管道结构健康监测问题上潜力巨大。

RESEARCH ON PIPELINE DEFORMATION IN PERMAFROST REGION USING INVERSE FINITE ELEMENT METHOD BASED ON IBEAM3 ELEMENT

Combined with strain-shape algorithm, shape sensing technology is able to achieve the mapping of the strain of measured points and their spatial position. This technology can truly reflect the spatial attitudes and shape changes of the objects to be measured, and can realize dynamic real-time monitoring. An inverse finite element method based on iBeam3 element is proposed to realize real-time monitoring of pipeline deformation in this paper. The theoretical framework model of inverse finite element method based on iBeam3 element is established; The rationality of this model is verified by experiments; The pipeline deformation test is designed in the permafrost area and the inverse finite element analysis model is established based on the surface strain information measured by the strain sensor; The reconstruction of the pipe shape in the whole freeze-thaw cycle is realized. The test results show that the method can not only monitor the complete deformation process of pipeline with freeze-thaw cycle in real time, but also ensure the accuracy. It has great potential in solving the health monitoring problem of pipeline structure in cold areas.