High precision structural displacement monitoring is challenging, but an effective method for structural health monitoring and particularly damage evaluation. In this paper, a high precision fiber Bragg grating (FBG) displacement sensor with embedded spring is developed to monitor structural displacement variation even at very small ranges. The principle of such monitoring is based on the central wavelength shifts in accordance with the displacement between measuring points. Calibration experiments are conducted to examine the performance of the innovative displacement sensor. The result indicates that the sensor has excellent linearity and repeatability, with the sensitivity coefficient being 23.96[Formula: see text]pm/mm, and the static relative error is 4.94% after three loading and unloading cycles. The displacement sensor therefore shows an excellent sensitivity and high precision for application. Moreover, it has been verified that this sensor is suitable and applicable for displacement monitoring in quasi-static experiment of structures.

中文翻译：

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结构健康监测高精度FBG位移传感器实验研究及误差分析

高精度结构位移监测具有挑战性，但却是结构健康监测尤其是损伤评估的有效方法。在本文中，开发了一种带有嵌入式弹簧的高精度光纤布拉格光栅 (FBG) 位移传感器，即使在非常小的范围内也能监测结构位移变化。这种监测的原理是基于中心波长随测量点之间的位移而变化。进行校准实验以检查创新位移传感器的性能。结果表明，该传感器具有良好的线性度和重复性，灵敏度系数为23.96[公式：见正文]pm/mm，经过三个加载和卸载循环后的静态相对误差为4.94%。因此，位移传感器显示出出色的灵敏度和高精度的应用。经验证，该传感器适用于结构准静态实验中的位移监测。