The strain-temperature cross-sensitivity problem easily occurs in the engineering strain monitoring of the self-sensing embedded with fiber Bragg grating (FBG) sensors. In this work, a theoretical investigation of the strain-temperature cross-sensitivity has been performed using the temperature reference grating method. To experimentally observe and theoretically verify the problem, the substrate materials, the preloading technique, and the FBG initial central wavelength were taken as main parameters. And a series of sensitivity coefficients calibration tests and temperature compensation tests have been designed and carried out. It was found that when the FBG sensors were embedded on different substrates, their coefficients of the temperature sensitivity were significantly changed. Besides, the larger the coefficients of thermal expansion (CTE) of substrates were, the higher the temperature sensitivity coefficients would be. On the other hand, the effect of the preloading technique and FBG initial wavelength was negligible on both the strain monitoring and temperature compensation. In the case of similar substrates, we did not observe any difference between temperature sensitivity coefficients of the temperature compensation FBG with one free end or two free ends. The curves of the force along with temperature were almost overlapped with minor differences (less than 1%) gained by FBG sensors and pressure sensors, which verified the accuracy of the temperature compensation method. We suggest that this work can provide efficient solutions to the strain-temperature cross-sensitivity for engineering strain monitoring with the self-sensing element embedded with FBG sensors.

钢绞线在复杂的工程环境中可能会出现断丝现象，为了有效识别断丝信号，制作了一种将光纤布拉格光栅（FBG）应变传感器内嵌预压至钢绞线中心丝的自感知钢绞线。分析自感知钢绞线对断丝信号识别的灵敏性，探讨了拉索损伤面积和损伤位置与断丝信号强弱的关联性。以普通钢绞线损伤面积、损伤位置和传感器位置为研究变量，对由16束普通钢绞线和3束自感知钢绞线组成的拉索展开三组张拉断丝实验。实验结果表明：各自感知钢绞线能精确识别断丝信号，且断丝信号与自感知钢绞线中FBG的分布位置无关；各自感知钢绞线识别到断丝信号的时间基本一致，且FBG传感器采集的断丝信号强弱与普通钢绞线的损伤位置和程度有关。

设计了一种在预应力钢绞线中心丝上设置倾斜凹槽封装光纤光栅的自感知钢绞线, 以解决体内预应力钢绞线其它传感器无安装空间, 易碎断导致封装成活率低以及监测量程不够等技术难题.理论分析了不同凹槽倾角封装的光纤光栅传感器的监测应变与钢绞线应变, 根据复合材料剪滞模型理论建立了二者之间的应变关系.以倾角为变化参数, 研制了系列光纤光栅自感知钢绞线, 并对其进行张拉试验, 测定光纤光栅传感器量程的变化情况.试验结果表明：该方法能有效扩大光纤光栅传感器的监测量程, 当倾斜角度为30°时, 所能监测的应变范围与0°相比, 提高了44%.采用该技术, 利用光纤光栅传感器对某高速公路预应力箱梁的施工张拉及服役进行实时监测, 传感器成活率为100%, 同时将光纤光栅的理论及标定应变关系与现场张拉及二次张拉的数据进行对比, 误差均在5%以内.该技术实现了对体内预应力钢绞线施工张拉和服役全生命周期的监测.

This paper reports the state of art in a variety of pressure and the detailed study of various matrix based pressure sensors. The performances of the bridges, buildings, etc. are threatened by earthquakes, material degradations, and other environmental effects. Structural health monitoring (SHM) is crucial to protect the people and also for assets planning. This study is a contribution in developing the knowledge about self-sensing smart materials and structures for the construction industry. It deals with the study of self-sensing as well as mechanical and electrical properties of different matrices based on pressure sensors. The relationships among the compression, tensile strain, and crack length with electrical resistance change are also reviewed.

研制了不需要外部附加微位移与微力传感器、采用自感知方法来获取压电微夹钳的钳指位移与夹持力的压电自感知微夹钳.根据压电陶瓷晶片在驱动电压与外力作用下发生变形会在其表面产生电荷的思想,提出了基于积分电荷的钳指位移与夹持力的自感知方法;基于Jan G.Smits的压电悬臂梁弯曲变形理论,给出了钳指位移与夹持力的自感知表达式,即用钳指上压电陶瓷晶片表面的电荷来表达钳指位移与夹持力.设计了获取晶片表面电荷的积分电路,给出了其平衡条件为晶片电容与其绝缘电阻之积同积分电容与反馈电阻之积相等.自感知验证实验结果表明:修正后在31.59 μm最大钳指位移范围内的自感知位移最大偏差为0.78 μm;在35.91 mN最大钳指夹持力范围内的自感知夹持力的最大偏差为0.24 mN.实验结果验证了所提自感知方法是有效的.