Thermal mechanical coupling decoupling method based on BOTDR (Brillouin Optical Time Domain Reflection) technology

Abstract

The invention discloses a thermal mechanical coupling decoupling method based on a BOTDR (Brillouin Optical Time Domain Reflection) technology. In engineering application, a thermal mechanical coupling process a mutual influencing process between two physical fields: a stress field and a temperature field, namely, stress deformation is influenced by temperature, and moreover, temperature change isinfluenced by the stress deformation. Due to a thermal mechanical coupling influence, an optical fiber itself changes along with the temperature change, and small change occurs in a strain and stresscorresponding relationship. According to the method, the small change is decoupled, so the strain and stress relationship is relatively accurate. In order to overcome the deficiency resulting from athermal mechanical coupling phenomenon in the prior art, the invention provides the thermal mechanical coupling decoupling method based on the BOTDR technology. The method is consistent with the strain-stress measurement of the BOTDR technology under the temperature change. The method comprises the steps of S1, calibrating the optical fiber; S2, separating a temperature and strain relationship; S3, establishing a strain and stress relationship; and S4, decoupling the thermal mechanical coupling.

Description

technical field [0001] The invention relates to a method for calculating the density of an unknown environment liquid based on BOTDR technology, which belongs to an engineering problem in the field of machine distributed optical fiber detection. Background technique [0002] Optical fiber sensing technology is a new type of sensing technology that emerged with the development of optical fiber technology and optical fiber communication technology in the 1970s. It uses light waves as the sensing signal and optical fiber as the transmission medium to perceive and detect external measured signals. It is very different from traditional electrical sensors in terms of sensing methods, sensing principles, and signal detection and processing. The optical fiber itself is dead, small in size, light in weight, easy to bend, resistant to electromagnetic interference, and has good radiation resistance. It is especially suitable for use in harsh environments such as flammable, explosive, s...

AI Technical Summary

Problems solved by technology

Some research objects are often not one point or several points, but a field with a certain spatial distribution, such as temperature field, stress field, vibration field, etc. This type of measured object not only involves a long distance and a wide range, but also has a three-dimensional space. Continuous distribution. At this time, single-point or even multi-point quasi-distributed sensing is no longer capable of sensing detection, and a fully distributed optical fiber sensing system emerges as the times require.

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