FBG Six-Dimensional Strain Sensing With Temperature Compensation
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Solution Overview
Problem
Conventional fiber grating spatial strain sensing apparatuses face issues with dispersed measurement points, large size, inaccurate temperature compensation, and severe measurement errors due to mutual-interference coupling effects, limiting accurate multidimensional strain measurement.
Innovation Solution
A FBGs-based six-dimensional strain sensor with six strain sensing units in X, Y, Z, XY, XZ, and YZ directions, integrated with a temperature sensing unit for compensation, and a multidimensional strain decoupling apparatus using a BP-neural network model for precise strain measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple independent FBG strain sensing apparatuses are used to measure spatial strains in different directions, then the measurement coverage is improved, but the device size increases and measurement points become dispersed
Solution Approach 1:
The patent combines six independent FBG strain sensing apparatuses into a single integrated six-dimensional strain sensor. The sensor integrates six strain sensing units with FBG elements oriented in three orthogonal directions (x, y, z axes), allowing simultaneous measurement of strains in all three spatial dimensions and their principal components within a compact unified structure, thereby maintaining comprehensive measurement coverage while reducing overall device size.
Solution Approach 2:
The six-dimensional strain sensor achieves multi-functionality by incorporating six strain sensing units that can simultaneously measure strains in multiple directions (εx, εy, εz, εxy, εxz, εyz). This universal design allows a single device to perform what previously required multiple separate apparatuses, improving adaptability while consolidating the device footprint.
2Adaptability or versatility
If multiple independent FBG strain sensing apparatuses are arranged to form an array, then spatial strains in different directions can be measured, but the measurement points become dispersed and temperature compensation accuracy deteriorates
Solution Approach 1:
The patent merges six strain sensing units and temperature compensation units into a single integrated sensor assembly. The temperature compensation unit is positioned in close proximity to all six strain sensing units within the same housing, ensuring uniform temperature exposure and enabling accurate simultaneous temperature compensation for all strain measurements, thereby eliminating the temperature compensation accuracy issues associated with dispersed independent apparatuses.
3Ease of manufacture
If conventional measurement method with specific structure and layout is used, then the apparatus is simple to manufacture, but mutual-interference coupling effects occur during strain measurement in multiple directions leading to severe measurement errors
Solution Approach 1:
The patent applies local quality by orienting the FBG elements in six different directions (along x, y, z axes and their combinations) within the sensing units. Each FBG is specifically oriented to detect strain in its particular direction, and the sensing units are positioned and oriented to minimize mutual interference. This directional differentiation allows simultaneous multidirectional measurement while reducing coupling effects between adjacent sensing elements.
Solution Approach 2:
The sensor is segmented into six independent strain sensing units, each with its own FBG element oriented in a specific direction. This segmentation allows each unit to measure strain independently in its designated direction, reducing mutual interference compared to a conventional unified structure. The six units work together as an integrated system while maintaining measurement independence through their segmented architecture and specific orientations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The sensor enables simultaneous monitoring of multidimensional strains with improved accuracy by decoupling interference effects, achieving precise spatial principal strain measurement and temperature compensation.
Implementation Method 1
Fiber grating spatial strain sensing shifts with a center wavelength generated by a fiber Bragg grating (FBG) due to external deformation
Data Source
AI summary
Provided is a fiber Bragg gratings (FBGs)-based six-dimensional strain sensor for monitoring a spatial principal strain, which belongs to the field of fiber grating strain sensing technologies. The FBGs-based six-dimensional strain sensor has six strain sensing units of a same structure that are arranged in six spatial directions of X, Y, Z, XY, XZ, and YZ, and also has a temperature sensing unit. By designing an integrated six-dimensional strain sensor, this application achieves simultaneous monitoring of strains in the six spatial directions, to obtain a distribution status of complex strains and the principal strain in internal space of a measured object. A six-dimensional strain sensor is designed with a multifunctional strain decoupling apparatus. A sensor strain decoupling model based on a BP-neural network is established according to calibration data of the decoupling apparatus. This application is applicable to the field of multidimensional spatial strain measuring.