Aiming at the requirement for high-precision tilt monitoring in the field of structural health monitoring(SHM),this paper proposes a sensitivity-enhanced tilt sensor based on a femtosecond fiber Bragg grating(FBG).Fir...Aiming at the requirement for high-precision tilt monitoring in the field of structural health monitoring(SHM),this paper proposes a sensitivity-enhanced tilt sensor based on a femtosecond fiber Bragg grating(FBG).Firstly,structural design of the tilt sensor was conducted based on static mechanics principles.By positioning the FBG away from the beam’s neutral axis,linear strain enhancement in the FBG was achieved,thereby improving sensor sensitivity.The relationship between FBG strain,applied force,and the offset distance from the neutral axis was established,determining the optimal distance corresponding to maximum strain.Based on this optimization scheme,a prototype of the tilt sensor was designed,fabricated,and experimentally tested.Experimental results show that the FBG offset distance yielding maximum sensitivity is 4.4 mm.Within a tilt angle range of−30°to 30°,the sensor achieved a sensitivity of 129.95 pm/°and a linearity of 0.9997.Compared to conventional FBG-based tilt sensors,both sensitivity and linearity were significantly improved.Furthermore,the sensor demonstrated excellent repeatability(error<0.94%),creep resistance(error<0.30%),and temperature stability(error<0.90%).These results demonstrate the sensor’s excellent potential for SHM applications.The sensor has been successfully deployed in an underground pipeline project,conducting long-term monitoring of tilt and deformation in the steel support structures,further proving its value for engineering safety monitoring.展开更多
A micro-displacement sensor based on fiber Bragg grating(FBG) is proposed. The device consists of a pair of FBGs with different central wavelengths fabricated by femtosecond laser phase mask method and a metal substra...A micro-displacement sensor based on fiber Bragg grating(FBG) is proposed. The device consists of a pair of FBGs with different central wavelengths fabricated by femtosecond laser phase mask method and a metal substrate with lever structure. The displacement is amplified by lever structure and it converts into axial tension of FBG, which has a high displacement sensitivity. The amplification factors obtained by theoretical analysis and finite element simulation are 2.67 and 2.50, respectively. The experimental results show that in the range of 0-50 μm the shift of FBG center wavelength is linearly related to the displacement of measured object and displacement sensitivity reaches 121 pm/μm. In addition, the cascaded FBG is used to compensate the temperature.展开更多
In this paper, the effects of packaging material and structure of fiber Bragg grating sensor performance are investigated. The effects of thermal expansion coefficient of different embedding materials on the temperatu...In this paper, the effects of packaging material and structure of fiber Bragg grating sensor performance are investigated. The effects of thermal expansion coefficient of different embedding materials on the temperature sensitivities of the FBG sensors are studied both theoretically and experimentally with good agreement, which provides a means for selection of FBG packaging material to achieve desired temperature sensitivity. We also demonstrate a 4-point bending structured FBG lateral force sensor that measures up to 242N force with well-preserved reflection spectrum, whereas for 3-point bending structure, multiple-peaks start to occur when applied force reaches 72N.展开更多
为研究光纤布拉格光栅(fiber Bragg grating,FBG)技术用于检测局部放电(简称局放)超声信号的灵敏度和抗干扰性能,在实验室搭建了基于FBG的局放检测系统,对自由微粒放电和悬浮放电2种类型的局放信号进行了检测,并将检测结果与基于压电陶...为研究光纤布拉格光栅(fiber Bragg grating,FBG)技术用于检测局部放电(简称局放)超声信号的灵敏度和抗干扰性能,在实验室搭建了基于FBG的局放检测系统,对自由微粒放电和悬浮放电2种类型的局放信号进行了检测,并将检测结果与基于压电陶瓷(piezoelectric,PZT)传感器的局放系统进行了对比。此外,针对变电站存在的振动干扰和强电磁干扰,对系统的抗干扰能力进行了对比实验研究。实验结果显示:对于25 p C的自由微粒放电及130 p C的悬浮放电,基于FBG的局放检测系统和传统PZT局放检测系统均可测得明显的信号,前者可以取得与后者接近相同的灵敏度;对于振动干扰的情况,FBG及PZT局放检测系统均会测得明显的干扰信号,但信号的形状完全不同;对于强电磁干扰的情况,PZT局放检测系统会受到明显的影响,但FBG局放检测系统则能完全避开强电磁干扰。综合各项实验结果可得,相较传统PZT局放检测系统,FBG局放检测系统的检测灵敏度几乎一致,但抗干扰性能较优。展开更多
文摘Aiming at the requirement for high-precision tilt monitoring in the field of structural health monitoring(SHM),this paper proposes a sensitivity-enhanced tilt sensor based on a femtosecond fiber Bragg grating(FBG).Firstly,structural design of the tilt sensor was conducted based on static mechanics principles.By positioning the FBG away from the beam’s neutral axis,linear strain enhancement in the FBG was achieved,thereby improving sensor sensitivity.The relationship between FBG strain,applied force,and the offset distance from the neutral axis was established,determining the optimal distance corresponding to maximum strain.Based on this optimization scheme,a prototype of the tilt sensor was designed,fabricated,and experimentally tested.Experimental results show that the FBG offset distance yielding maximum sensitivity is 4.4 mm.Within a tilt angle range of−30°to 30°,the sensor achieved a sensitivity of 129.95 pm/°and a linearity of 0.9997.Compared to conventional FBG-based tilt sensors,both sensitivity and linearity were significantly improved.Furthermore,the sensor demonstrated excellent repeatability(error<0.94%),creep resistance(error<0.30%),and temperature stability(error<0.90%).These results demonstrate the sensor’s excellent potential for SHM applications.The sensor has been successfully deployed in an underground pipeline project,conducting long-term monitoring of tilt and deformation in the steel support structures,further proving its value for engineering safety monitoring.
基金Projects(51875585, 51875584, 51935013) supported by the National Natural Science Foundation of ChinaProject(2020JJ4247) supported by the Natural Science Foundation of Hunan Province,ChinaProject(ZHD202001) supported by the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory,China。
文摘A micro-displacement sensor based on fiber Bragg grating(FBG) is proposed. The device consists of a pair of FBGs with different central wavelengths fabricated by femtosecond laser phase mask method and a metal substrate with lever structure. The displacement is amplified by lever structure and it converts into axial tension of FBG, which has a high displacement sensitivity. The amplification factors obtained by theoretical analysis and finite element simulation are 2.67 and 2.50, respectively. The experimental results show that in the range of 0-50 μm the shift of FBG center wavelength is linearly related to the displacement of measured object and displacement sensitivity reaches 121 pm/μm. In addition, the cascaded FBG is used to compensate the temperature.
基金Supported by Science & Engineering Research Council of Singapore (052 118 0052)
文摘In this paper, the effects of packaging material and structure of fiber Bragg grating sensor performance are investigated. The effects of thermal expansion coefficient of different embedding materials on the temperature sensitivities of the FBG sensors are studied both theoretically and experimentally with good agreement, which provides a means for selection of FBG packaging material to achieve desired temperature sensitivity. We also demonstrate a 4-point bending structured FBG lateral force sensor that measures up to 242N force with well-preserved reflection spectrum, whereas for 3-point bending structure, multiple-peaks start to occur when applied force reaches 72N.
文摘为研究光纤布拉格光栅(fiber Bragg grating,FBG)技术用于检测局部放电(简称局放)超声信号的灵敏度和抗干扰性能,在实验室搭建了基于FBG的局放检测系统,对自由微粒放电和悬浮放电2种类型的局放信号进行了检测,并将检测结果与基于压电陶瓷(piezoelectric,PZT)传感器的局放系统进行了对比。此外,针对变电站存在的振动干扰和强电磁干扰,对系统的抗干扰能力进行了对比实验研究。实验结果显示:对于25 p C的自由微粒放电及130 p C的悬浮放电,基于FBG的局放检测系统和传统PZT局放检测系统均可测得明显的信号,前者可以取得与后者接近相同的灵敏度;对于振动干扰的情况,FBG及PZT局放检测系统均会测得明显的干扰信号,但信号的形状完全不同;对于强电磁干扰的情况,PZT局放检测系统会受到明显的影响,但FBG局放检测系统则能完全避开强电磁干扰。综合各项实验结果可得,相较传统PZT局放检测系统,FBG局放检测系统的检测灵敏度几乎一致,但抗干扰性能较优。
