为了拓展水面防波堤的有效消波周期范围,本文应用Bragg共振,开展多重水面穿透箱体与潜堤组合结构物的消波性能研究。基于时域势流理论,采用去奇异边界元方法(Desingularized Boundary Integral Equation Method,DBIEM),建立数值波浪水槽...为了拓展水面防波堤的有效消波周期范围,本文应用Bragg共振,开展多重水面穿透箱体与潜堤组合结构物的消波性能研究。基于时域势流理论,采用去奇异边界元方法(Desingularized Boundary Integral Equation Method,DBIEM),建立数值波浪水槽,数值计算了规则波与多重等间距布置的水面箱体与水底潜堤组合的结构物之间的相互作用。通过反射系数和透射系数分析了组合结构物的Bragg共振发生点位置、反射强度和消波性能。通过将数值结果与文献数据进行比较,验证了本文数值计算方法的有效性。计算结果给出了透射系数和反射系数随2S/λ(S为相邻结构物的中心间距,λ为入射波长)的变化趋势。结果表明,规则波在多重结构物中传播时会发生Bragg共振,此时其对波浪的衰减效果明显优于单体结构物。对于多重结构物,随着其数量、宽度、水面箱体浸深的增加,Bragg共振反射强度增加,不仅降低了透射系数,而且提升了对长周期波浪的消波能力;而增加相邻组合结构物间隙拓宽了有效消减波浪的周期范围。潜堤的存在加强了防波堤对长周期波的消浪能力。本研究为组合形式的防波堤设计提供参考。展开更多
Fiber Bragg grating(FBG)sensors are extensively used in various sensing applications due to their high sensitivity.However,they are inherently sensitive to both strain and temperature,with a cross-sensitivity problem,...Fiber Bragg grating(FBG)sensors are extensively used in various sensing applications due to their high sensitivity.However,they are inherently sensitive to both strain and temperature,with a cross-sensitivity problem,making it impossible to simultaneously monitor these two parameters using the Bragg wavelength shifts of a single uniform FBG.In this study,we bend the FBG pigtail to cause bending loss.The peak power of the FBG is used as the second characterization quantity.Our experimental results show that the Bragg wavelength sensitivities to strain(K_(ε))and temperature(K_(T))are 0.17 pm/ue and 16.5 pm/℃,respectively.Additionally,the peak power sensitivities to strain(P_(ε))and temperature(P_(T))are-0.00202 dBm/μεand-0.06 dBm/℃,respectively.The linear correlation coefficients for these measurements are all above 0.996.In this way,it is possible to simultaneously measure both strain and temperature using a single uniform FBG.展开更多
A compact and highly sensitive gas pressure and temperature sensor based on Fabry-Pérot interferometer(FPI)and fiber Bragg grating(FBG)is proposed and demonstrated experimentally in this paper.The theoretical mod...A compact and highly sensitive gas pressure and temperature sensor based on Fabry-Pérot interferometer(FPI)and fiber Bragg grating(FBG)is proposed and demonstrated experimentally in this paper.The theoretical model for pressure and temperature sensing is established.Building on this foundation,a novel micro silicon cavity sensor structure sensitive to pressure is devised downstream of an FBG.The concept of separate measurement and the mechanisms enhancing pressure sensitivity are meticulously analyzed,and the corresponding samples are fabricated.The experimental results indicate that the pressure sensitivity of the sensor is-747.849 nm/MPa in 0—100 k Pa and its linearity is 99.7%and it maintains good stability in 150 min.The sensor offers the advantages of compact size,robust construction,easy fabrication,and high sensitivity,making it potentially valuable for micro-pressure application.展开更多
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
Purpose–To address the encapsulation challenge of fiber Bragg grating(FBG)sensors in complex railway environments,this paper designs a clip-on composite sensor enabling installation-friendly deployment and long-term ...Purpose–To address the encapsulation challenge of fiber Bragg grating(FBG)sensors in complex railway environments,this paper designs a clip-on composite sensor enabling installation-friendly deployment and long-term axle counting system monitoring.Design/methodology/approach–Wheel–rail mechanical behavior was simulated via finite element analysis(FEA)to determine optimal sensor placement.A clip-on composite sensor was subsequently engineered.Stress transduction efficacy was validated through FEA quantification of stress responses at the axle counter location.Findings–The proposed FBG axle counter integrates temperature compensation and anti-detachment monitoring as well as advantages such as simplified installation with minimal maintenance and sustained operational reliability.It effectively transmits stress,yielding a measured strain of 39μe under static loading conditions without sensitivity-enhancing elements.Originality/value–This study performs FEA of wheel-rail stress distribution and engineers the dual-slot composite sensor,FEAwas conducted to quantify the stress magnitude at the axle sensor position of the dual-slot composite sensor.Additionally,FEA was performed on sensors with different structural configurations,including adjustments to the axle sensor position,number of slots and axle position.The results confirmed that the designed composite sensor exhibits superior stress transfer characteristics.展开更多
文摘为了拓展水面防波堤的有效消波周期范围,本文应用Bragg共振,开展多重水面穿透箱体与潜堤组合结构物的消波性能研究。基于时域势流理论,采用去奇异边界元方法(Desingularized Boundary Integral Equation Method,DBIEM),建立数值波浪水槽,数值计算了规则波与多重等间距布置的水面箱体与水底潜堤组合的结构物之间的相互作用。通过反射系数和透射系数分析了组合结构物的Bragg共振发生点位置、反射强度和消波性能。通过将数值结果与文献数据进行比较,验证了本文数值计算方法的有效性。计算结果给出了透射系数和反射系数随2S/λ(S为相邻结构物的中心间距,λ为入射波长)的变化趋势。结果表明,规则波在多重结构物中传播时会发生Bragg共振,此时其对波浪的衰减效果明显优于单体结构物。对于多重结构物,随着其数量、宽度、水面箱体浸深的增加,Bragg共振反射强度增加,不仅降低了透射系数,而且提升了对长周期波浪的消波能力;而增加相邻组合结构物间隙拓宽了有效消减波浪的周期范围。潜堤的存在加强了防波堤对长周期波的消浪能力。本研究为组合形式的防波堤设计提供参考。
基金supported by the Fundamental Research Funds for the Central Universities(No.2024JBZX017)。
文摘Fiber Bragg grating(FBG)sensors are extensively used in various sensing applications due to their high sensitivity.However,they are inherently sensitive to both strain and temperature,with a cross-sensitivity problem,making it impossible to simultaneously monitor these two parameters using the Bragg wavelength shifts of a single uniform FBG.In this study,we bend the FBG pigtail to cause bending loss.The peak power of the FBG is used as the second characterization quantity.Our experimental results show that the Bragg wavelength sensitivities to strain(K_(ε))and temperature(K_(T))are 0.17 pm/ue and 16.5 pm/℃,respectively.Additionally,the peak power sensitivities to strain(P_(ε))and temperature(P_(T))are-0.00202 dBm/μεand-0.06 dBm/℃,respectively.The linear correlation coefficients for these measurements are all above 0.996.In this way,it is possible to simultaneously measure both strain and temperature using a single uniform FBG.
基金supported in part by the National Natural Science Foundation of China(Nos.61735014 and 61927812)the Shaanxi Provincial Education Department(No.18JS093)+2 种基金the Natural Science Basic Research Program of Shaanxi Province(No.2024JC-YBMS-530)the Operation Fund of Logging Key Laboratory of Group Company(No.2021DQ0107-11)the Graduate Student Innovation Fund of Xi’an Shiyou University(No.YCS23213193)。
文摘A compact and highly sensitive gas pressure and temperature sensor based on Fabry-Pérot interferometer(FPI)and fiber Bragg grating(FBG)is proposed and demonstrated experimentally in this paper.The theoretical model for pressure and temperature sensing is established.Building on this foundation,a novel micro silicon cavity sensor structure sensitive to pressure is devised downstream of an FBG.The concept of separate measurement and the mechanisms enhancing pressure sensitivity are meticulously analyzed,and the corresponding samples are fabricated.The experimental results indicate that the pressure sensitivity of the sensor is-747.849 nm/MPa in 0—100 k Pa and its linearity is 99.7%and it maintains good stability in 150 min.The sensor offers the advantages of compact size,robust construction,easy fabrication,and high sensitivity,making it potentially valuable for micro-pressure application.
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.
文摘Purpose–To address the encapsulation challenge of fiber Bragg grating(FBG)sensors in complex railway environments,this paper designs a clip-on composite sensor enabling installation-friendly deployment and long-term axle counting system monitoring.Design/methodology/approach–Wheel–rail mechanical behavior was simulated via finite element analysis(FEA)to determine optimal sensor placement.A clip-on composite sensor was subsequently engineered.Stress transduction efficacy was validated through FEA quantification of stress responses at the axle counter location.Findings–The proposed FBG axle counter integrates temperature compensation and anti-detachment monitoring as well as advantages such as simplified installation with minimal maintenance and sustained operational reliability.It effectively transmits stress,yielding a measured strain of 39μe under static loading conditions without sensitivity-enhancing elements.Originality/value–This study performs FEA of wheel-rail stress distribution and engineers the dual-slot composite sensor,FEAwas conducted to quantify the stress magnitude at the axle sensor position of the dual-slot composite sensor.Additionally,FEA was performed on sensors with different structural configurations,including adjustments to the axle sensor position,number of slots and axle position.The results confirmed that the designed composite sensor exhibits superior stress transfer characteristics.
