Measurement of stress concentrations using embedded optical fiber Bragg grating sensors
Measurement of stress concentrations using embedded optical fiber Bragg grating sensors
复制标题
使用嵌入式光纤布拉格光栅传感器测量应力集中
DOI：
10.1117/12.349730
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
R. Salathé
中科院分区：
文献类型：
--
作者：
K. Peters;Michel Studer;J. Botsis;A. Iocco;H. Limberger;R. Salathé
本文研究了使用嵌入式光纤布拉格光栅来测量固体结构中应力集中附近的应变。由于应力集中的性质（即应变场的强非均匀性），反射中的光栅谱保持恒定带宽的单峰的假设可能不成立。紧致张力试样包括一个控制缺口形状与嵌入光纤布拉格光栅在相同的位置，但具有不同的规长。在给定的载荷条件下，透射光谱在这些试样之间是不同的。这种变化是由于量规长度的不同造成的。利用电子散斑干涉法测量的试样表面应变场和光栅的离散化模型，对透射光谱进行了解析验证。因此，考虑到应变场的非均匀性，光纤布拉格计可以作为应力集中附近的嵌入式应变计。由于测量在特定量规长度内的分布特性，光纤布拉格量规在测量纤维增强复合材料中的脱粘方面具有很大的潜力。
This paper investigates the use of embedded optical fiber Bragg gratings to measure strain near a stress concentration within a solid structure. Due to the nature of a stress concentration (i.e. the strong non-uniformity of the strain field) the assumption that the grating spectrum in reflection remains a single peak with a constant bandwidth may not be valid. Compact tension specimens including a controlled notch shape are fabricated with embedded optical fiber Bragg gratings at identical locations but with different gauge lengths. The spectra in transmission varies between such specimens for given loading conditions. This variation is shown to be due to the difference in gauge length. By using the strain field measured on the specimen surface with electronic speckle pattern interferometry and a discretized model of the grating, the spectra in transmission are then verified analytically. Thus, by considering the non-uniformity of the strain field, the optical fiber Bragg gauge functions well as an embedded strain gauge near the stress concentration. Due to the distributed nature of the measurements within a specific gauge length, the optical fiber Bragg gauge has a large potential to measure debonding in fiber reinforced composites.