基于稀土5d-4f宽带发光的荧光应力传感技术

发布时间：2018-09-18 14:10

【摘要】：目前荧光应力传感方法主要包括Cr~(3+)荧光压谱技术、应力发光与稀土荧光压谱技术。稀土元素丰富的荧光谱线给荧光压谱技术提供了更多的敏感材料选项。本文对这三种应力传感技术进行了归纳比较,并指出了稀土荧光压谱技术的独特优势。力敏光谱技术通常使用谱峰频移表征应力,但一般情况下用于应力传感监测信号的谱带峰位移动极小,难以准确地检测。本课题组的研究中设计了新的传感信号--发射光谱谱带的重心波长以及荧光强度比。它们都随着压应力的变化而单调地改变。本文研究了两种宽带荧光材料的应力传感特性。采用新的传感信号后,荧光谱带的移动能较精确地检测到,压谱系数较常用的红宝石荧光压谱系数大了约3个数量级。实验中采用405nm激发光源,搭建反射式测量光路,利用光纤光谱仪记录一系列稳态发射光谱,经过数据处理最终给出了每种传感特征随应力变化的传感方程,并对其传感性能做了简要分析,具体结果如下:(1)YAG:Ce~(3+):压应力导致谱带蓝移,实验中测量的压应力范围0~1.59 MPa,得到谱带重心的压应力传感方程为λ=572.6-0.72σ+0.22σ~2,外应力较大时局部曲线近似呈线性,灵敏度约0.3 nm/MPa,此灵敏度是已知的相应荧光粉在静水压环境中压谱系数的90倍。并得到双波长强度比(I(570nm)/I(510nm))与积分强度比(I(420nm~570nm)/I(570nm~800nm))的压应力传感方程分别为1)FIR=8.4-1.74σ+0.54σ~2和2)I-FIR=0.79+0.03σ-0.0092σ~2。0.5 nm分辨率的光谱仪与5.4 nm分辨率的光谱仪的测量结果表明,光谱仪分辨率对应力传感精度没有明显影响。分辨率优于0.08 MPa。(2)SrSiAlN_3:Eu~(2+):分别测试分析了荧光样品压应力与弯曲应力对荧光光谱的影响。1、压应力:压应力导致谱带蓝移,压应力范围0~5.83 MPa,得到谱带重心与均值波长的压应力传感方程分别为1)λ=625.1-0.16σ和2)λ=630.3-0.138σ。并得到双波长强度比(I(632nm)/I(582nm))与积分强度比(I(628nm~800nm)/I(240nm~628nm))的压应力传感方程分别为3)FIR=2.097-0.023σ和4)I-FIR=0.8814-0.0063σ。分辨率优于0.28 MPa。2、弯曲应力:弯曲时压应力导致谱带蓝移,曲率范围0~16.03m~(-1),积分强度比-曲率曲线局部近似呈线性(I-FIR=I(178nm~607nm)/I(607nm~1000nm)),灵敏度约0.0033m。谱带重心法分辨率不足以探测这种小的弯曲。总体上,相比于峰值波长频移传感应力,重心方法与荧光强度比法的灵敏度更高、对设备性能要求低,且能测量分辨兆帕以下的微小应力。此外,积分强度比法还可以用于弯曲应力或曲率的传感。这些新型的应力传感方法可用于工件表层应力及残余应力的非接触测量,在机械工程领域有良好的应用前景。
[Abstract]:At present, the main methods of fluorescence stress sensing include Cr~ (3) fluorescence pressure spectroscopy, stress luminescence and rare earth fluorescence pressure spectroscopy. The rich fluorescence lines of rare earth elements provide more sensitive material options for fluorescence spectroscopy. In this paper, the three stress sensing techniques are summarized and compared, and the unique advantages of rare earth fluorescence pressure spectroscopy are pointed out. Stress is usually characterized by spectral peak shift in force sensitive spectroscopy, but it is difficult to accurately detect the peak position of spectrum band which is used for monitoring signal of stress sensing in general. In the research of our group, a new sensing signal-emission spectral band has been designed for the wavelength of center of gravity and the ratio of fluorescence intensity. They all change monotonously with the change of compressive stress. In this paper, the stress sensing characteristics of two kinds of broadband fluorescent materials are studied. With the new sensing signal, the shift energy of the fluorescence band can be detected more accurately, and the pressure spectrum number is about 3 orders of magnitude larger than that of the ruby spectrum. In the experiment, the 405nm excitation light source is used to set up the reflective measuring light path, and a series of steady state emission spectra are recorded by using the optical fiber spectrometer. After data processing, the sensing equations of each sensing characteristic varying with the stress are given. The sensing performance is briefly analyzed. The results are as follows: (1) YAG:Ce~ (3): the compressive stress results in the blue shift of the spectrum band. The compressive stress range measured in the experiment is 0 ~ 1.59 MPa,. The pressure stress sensing equation of the spectral center of gravity is 位 _ (572.6-0.72) 蟽 _ (0.22) 蟽 ~ (2), and the local curve is approximately linear when the external stress is large. The sensitivity is about 0. 3 nm/MPa,. The sensitivity is 90 times of that of the corresponding phosphors in hydrostatic pressure. The compressive stress sensing equations of (I (570nm / I (510nm) and (I (420nm~570nm / I (570nm~800nm) are 1) FIR=8.4-1.74 蟽 0.54 蟽 2 and 2) I-FIR=0.79 0.03 蟽 -0.0092 蟽 -2.0.5 nm resolution spectrometer and 5.4 nm resolution spectrometer, respectively. The resolution of the spectrometer has no obvious effect on the precision of the stress sensing. The resolution is better than 0.08 MPa. (2) SrSiAlN_3:Eu~ (2): the influence of compressive stress and bending stress on the fluorescence spectrum is measured and analyzed, respectively. The compressive stress: compressive stress leads to the blue shift of spectral band. The compressive stress sensing equations of the spectral center of gravity and the mean wavelength of the spectral band are 1) 位 ~ (1) 625.1-0.16 蟽 and 2) 位 ~ (3) 0.3-0.138 蟽, respectively, in the compressive stress range of 0 ~ 5.83 MPa,. The compressive stress sensing equations of double wavelength ratio (I (632nm) / r I (582nm) and integral intensity ratio (I (628nm~800nm) / r I (240nm~628nm) are 3) FIR=2.097-0.023 蟽 and 4) I-FIR=0.8814-0.0063 蟽, respectively. The resolution is better than 0. 28 MPa.2, bending stress: the compressive stress results in the blue shift of spectral band, the curvature range is 0 ~ (16. 03) m ~ (-1), and the integral intensity ratio-curvature curve is approximately linear (I-FIR=I (178nm~607nm) / I (607nm~1000nm), sensitivity about 0. 0033 m). The spectral band barycenter resolution is not sufficient to detect this small bend. In general, compared with the peak wavelength frequency shift induction force, the method of center of gravity and fluorescence intensity has higher sensitivity, lower requirements for equipment performance, and can be used to measure and distinguish tiny stresses below MPA. In addition, the integral strength ratio method can also be used for sensing bending stress or curvature. These new stress sensing methods can be used for non-contact measurement of surface stress and residual stress of workpiece, and have a good application prospect in mechanical engineering.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O614.33;O657.3

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