光纤自传感混杂BFRP张弦梁力学性能优化及自监测研究

With the development of architecture function, the demand for structural span, load capacity and safety intelligent control is getting to rich. The superiority of the beam string structure has become increasingly prominent. Based on analysis of shape optimization and elasto-plastic limit bearing capacity, a new intelligent beam string structure-optical fiber and self-sensing hybrid BFRP beam string structure is proposed. It's mechanical response and self monitoring performance is researched in this project. The main contents include: 1)by continuum theory and numerical analysis, present the design method of various beam string structures based on shape optimization. Then, by using the numerical model and measured data, obtain the distribution and characteristics of internal force and deformation on beam string structure during the period of construction and service. 2)Research on the key member local damage evaluation method of beam string structure based on elasto-plastic ultimate capacity analysis. Study on the evolution law of structural response after cable local failure and beam local failure. Then find the stress sensitive zone location of the beam string structure. 3)Based on the characteristics of distributed fiber sensing, propose a new type of self-sensing hybrid BFRP cable or sheet, in which the optical fiber composite to BFRP. So, the beam or cable element self monitoring is realized. Using the unit strain information from self monitoring and according to the fiber model theory and the strain modal analysis theory, propose the local damage identification method and the evaluation method of structural damage. It puts forward an important basis for the design and safe assessment of beam string structure.

随着建筑功能对结构跨度、荷载能力以及安全智能化控制需求的不断提高，张弦梁结构的优越性日益凸显。本课题基于形状优化和弹塑性极限承载力分析，提出一种新型光纤自传感混杂BFRP张弦梁，并对其力学响应及自监测性能进行了研究。主要研究包括：1)由连续化理论，基于数值分析提出基于形状优化的各类张弦梁结构的设计方法，并利用数值模拟和实测数据获取张弦梁结构施工和使用阶段内力与变形的分布规律及特点；2)基于弹塑性分析对张弦梁结构关键构件局部损伤评价方法进行研究。对突发事件下部分梁索单元失效后的结构响应演化规律进行分析，确定张弦梁结构的受力敏感区域位置；3)基于分布式光纤传感的特性，提出将光纤复合进BFRP材料制备自传感混杂BFRP索和片材,实现梁索单元自监测。利用自监测的单元应变信息，结合纤维模型理论和应变模态分析理论，提出局部损伤识别和结构损伤评价方法，为张弦结构的设计和安全评估提出重要依据。

光纤自传感BFRP张弦梁因其张弦结构形式的简洁、空间受力性能的优越，玄武岩纤维增强材料（BFRP）耐候性能的良好、性价比较高等突出优点成为结构工程研究的重要内容。本项目旨在开展张弦梁结构形态与力学性能间相关性及优化设计方法的研究，以及此类大跨预应力结构在材料的可替换性、耐候性与结构的智能自监测性能的探索。为此，先后进行了基于平衡荷载态的优化理论模型研究，确立了形状优化后的张弦梁结构整体优化方法并分析各类结构参数对结构受力的影响规律。系统研究了以双向张弦梁为代表的结构失效机制、弹塑性承载力的各影响参数以及构件安全性和结构整体性之间的力学响应关系。研究了光纤自传感混杂BFRP索的力学性能。基于索的等应变受力，试验模拟不同配比的光纤自传感混杂BFRP索的张拉受力过程，揭示了混杂BFRP索的力学性能特征以及其中不同材料间的受力差异和协同工作性，探讨了光纤传感器在预应力索中的适用性。基于BFRP光纤传感器的制备可行性，提出了光纤自传感混杂BFRP张弦梁基于力学性能和耐久性的设计方法。本研究有助于实现一种智能自传感预应力张弦结构，完美地将结构构件的力学性能和智能自监测性能综合高效地结合，对结构从施工到运营的整体监控以及灾后加固等具有重要意义。