损伤状态下光纤应变传递及其在多层路面的应用

发布时间：2018-02-11 18:06

本文关键词： 光纤传感器应变传递理论误差修正沥青路面多层介质结构健康监测性能评定　出处：《大连理工大学》2015年博士论文　论文类型：学位论文

【摘要】：路面结构由于组成材料的多介质和层间接触条件的复杂性,其力学响应和损伤演化机理难以通过力学理论或有限元仿真较准确地获取,而室内实验结果则受模型尺寸和荷载简化的影响。因此,采用光纤传感技术对路面内部应力和损伤状态进行较准确地监测,有效地评定实际路面的结构性能,为路面的维护和设计提供科学建议,具有重要价值。然而,为提升传感器在工程结构长期测试中的耐久性,需要对光纤感知元件进行封装。由于保护层、粘贴层等中间介质的存在,光纤感知应变不能完全代表基体的真实应变。因此,发展了应变传递理论,以建立光纤感知应变和基体应变之间的定量关系,修正应变传递误差,提升工程化传感器的测试准确性。国内外已有较多工作研究应变传递误差修正理论,但是有较多方面如力学模型与实测工程的关联度、假设与受力状态的匹配程度等还不完善,需要进一步的研究。尤其当被测结构对象为沥青路面基体时,传感器的误差修正问题显得更加重要和迫切。本文针对传感器用于一般结构和沥青路面及其典型损伤状态下的应变传递机理进行了理论研究,同时提出了基于应变传递理论的传感器优化设计方法及优先设计指标,在此基础上研制了满足沥青路面结构复杂应力测试的系列传感器,发展了兼顾结构局部(损伤)和整体力学形态的变标距测试技术和OF(Optical fiber)/FBG(Fiber Bragg grating)测试技术,并将其用于沥青路面的现场监测,实现了基于较长期监测数据的路面结构性能评定。论文主要内容包括：(1)根据被测基体材质、损伤特征及荷载模式的不同,建立了光纤传感器埋入和外贴于一般结构及其损伤(如弹塑性、塑性、剥离及疲劳)状态下的力学测试模型,分别对其应变传递机理进行了理论分析,推导得出了传感测试模型无损及有损伤情况下的误差修正公式,并基于所推导的静态和动态条件下弹性阶段的应变传递理论对影响应变传递效率的参数进行了敏感性分析。(2)针对沥青路面的施工特点和损伤特征,对埋入沥青路面的方形基体材料封装FBG和胶浆封装分布式光纤传感器的应变传递机理进行了理论分析,讨论了基体的粘弹性特征、蠕变效应及低温裂缝损伤状态下的误差修正公式,并基于推导的应变传递理论间接地实现了层间剥离损伤的监测。(3)根据变形传递方式的不同对外贴和埋入式光纤传感器进行了系统的归类和力学机理分析,提出了基于应变传递理论的工程化光纤传感器优化设计方法及其优先设计指标,并在此基础上研制了满足沥青路面结构复杂应力测试的系列新型FBG和光纤传感器,提供了相应的误差修正公式,通过基础实验论证了其工程可用性。(4)在系列传感器成功研制的基础上,针对长距离路面局部损伤和整体力学性能的测试需求,发展了表征结构局部损伤全历程信息的变标距测试技术、兼顾结构整体和局部性态的OF/FBG测试技术,并分别通过基础实验论证了其用于路面结构全尺度智能监测的可行和有效性。(5)基于前述理论推导、方法探讨及实验论证分析,将系列光纤传感器埋入两种沥青路面多层介质结构,对其在温度场变化和车辆荷载作用下的较长期力学响应进行了连续监测,并通过积累的有效变形数据对沥青路面的结构性能进行了评定,为路面结构的养护和设计提供了建议。
[Abstract]:Because of the complexity of the pavement structure layer and the contact condition of multi media material between the response and the damage evolution mechanism to mechanics theory or finite element simulation accurately obtain the mechanics, and experimental results are affected by the simplified model size and load. Therefore, by accurately monitoring on the surface and internal stress the damage state with optical fiber sensing technology, the actual pavement structure performance evaluation effectively, provide scientific advice for the design and maintenance of the road, has an important value. However, for the improvement of durability sensor in the long-term test in engineering construction, the need for encapsulation of the optical fiber sensing element. The protective layer, the middle layer of the medium paste true strain, strain sensing fiber can not fully represent the matrix. Therefore, the development of the strain transfer theory, to establish a quantitative perception between the fiber strain and matrix strain. System error transfer correction accuracy test strain, enhance engineering sensor. Transmission error correction theory at home and abroad there have been many research work strain, but related aspects such as more degrees of mechanical model and actual engineering, hypothesis and stress state of the matching degree is not perfect, need further research. Especially when the measured structure the object for asphalt pavement base, sensor error correction problem becomes more and more important and urgent. The transfer mechanism of strain sensor for asphalt pavement and its general structure and typical damage conditions were studied, and put forward the optimization design method of sensor strain transfer theory and design based on priority index, on the basis of the development to meet the asphalt pavement structure should be complex series of sensors force test, the development of both the local structure (damage) and the whole mechanical form variable The gauge test technology and OF (Optical fiber) /FBG (Fiber Bragg grating) testing technology and its application in field monitoring of asphalt pavement, the pavement performance evaluation is based on long-term monitoring data. The main contents include: (1) according to the measured matrix material, damage characteristics and load mode types. The establishment of the optical fiber sensors and affixed to the general structure and damage (such as plastic, plastic, spalling and fatigue) under the condition of mechanical testing model, respectively. The strain transfer mechanism was analyzed in theory, deduces the model test and nondestructive sensing error modified formula of damage, and elastic strain stage of static and dynamic conditions is based on the theory of strain transfer parameters and transmission efficiency of the sensitivity analysis. (2) according to the construction characteristics and damage characteristics of asphalt pavement, the asphalt buried Strain transfer mechanism of pavement square matrix material encapsulated FBG and glue package distributed optical fiber sensor is analyzed and discussed the viscoelastic properties of the matrix, the formulae of error correction effect and creep damage state under low temperature crack, and transfer theory indirectly realize the delamination damage monitoring is based on strain (3. According to the different modes of deformation transfer) and externally bonded fiber sensors were analyzed and classified and mechanics system, based on the strain transfer theory of engineering fiber sensor optimization design method and design the priority index, and on the basis of the development of asphalt pavement structure meet the complex stress test series model FBG and optical fiber the sensor, provides the corresponding error correction formula, based on experiments to prove its usability engineering. (4) developed in series sensor base On the basis, according to test requirements of local road damage and overall mechanical properties of long distance, the development of the whole process of local damage information representation structure of variable gauge testing technology, testing technology of both OF/FBG overall structure and local behavior, and are based on experiments to prove its feasibility and validity for full scale intelligent pavement structure monitoring. (5) the theory based on the analysis and experimental results demonstrate that the series of fiber optic sensors embedded in two kinds of asphalt pavement in the multi-layer structure, and the change of temperature field under vehicle load mechanical response of long period continuous monitoring, and through effective deformation data accumulated on the performance of asphalt pavement structure evaluation is carried out, and provides suggestions for design and maintenance of pavement.

【学位授予单位】：大连理工大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U416.217

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