Fiber grating strain sensor and packaging method thereof

By adopting a design in the fiber optic strain sensor that pre-stretches and then directly fixes it inside the fiber core, the measurement deviation caused by threaded fit clearance and thermal expansion and contraction is solved, thus achieving long-term stability and measurement accuracy of the sensor.

CN121067741BActive Publication Date: 2026-06-30HUADIAN HEAVY IND CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
HUADIAN HEAVY IND CO LTD
Filing Date
2025-07-17
Publication Date
2026-06-30

AI Technical Summary

Technical Problem

The strain gratings of existing fiber Bragg grating strain sensors are fixed by post-tensioning, which leads to deviations in the test data. This is mainly due to loosening and creep problems caused by the thread fit clearance and thermal expansion and contraction of metal parts.

Method used

The design adopts a pre-tensioned and directly fixed inside the fiber core, eliminating mechanical adjustment components such as nuts and metal tubes. By directly fixing the fiber grating assembly to the fiber core structure, an inseparable whole is formed, ensuring that the pretension value remains stable during long-term use.

Benefits of technology

This solution addresses measurement biases caused by environmental changes in sensors, reduces manufacturing complexity and maintenance costs, and improves long-term measurement accuracy and stability.

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Abstract

This invention discloses a fiber Bragg grating strain sensor and its packaging method. The fiber Bragg grating strain sensor includes: a fiber core structure, which is expandable and adaptable for connection to the object being measured; and a fiber Bragg grating assembly, which is fixedly connected to the fiber core structure. The fiber Bragg grating assembly includes an optical fiber and a strain grating, which are connected together. After pre-tensioning, the optical fiber and strain grating are directly fixed inside the fiber core structure, with the axial direction of the strain grating being the same as the expansion and contraction direction of the fiber core structure. This invention, through the process of directly fixing the pre-tensioned assembly inside the fiber core, eliminates mechanical adjustment components such as nuts and metal tubes, avoiding the influence of threaded clearance and thermal expansion and contraction on the pre-tension value. The fiber Bragg grating assembly and the fiber core structure are directly fixed as an inseparable whole, ensuring the stability of the pre-tension value during long-term use, fundamentally solving the creep problem and ensuring the accuracy of long-term measurement data.
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