Optical Fibre Flatness Roller for High-Resolution Strain Sensing
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Solution Overview
Problem
Conventional flatness rollers in rolling operations, particularly for thin metal sheets, suffer from insufficient spatial resolution, sensitivity, dynamic response, and bandwidth, leading to inaccurate flatness measurement and high maintenance costs.
Innovation Solution
A flatness roller design featuring a cylindrical body with radially extending cavities and slots, equipped with optical fibre strain sensors aligned to maximize sensitivity and minimize cross-talk, allowing for precise strain measurement and improved dynamic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional flatness rollers are used in rolling operations, then the structure is simple and manufacturing is easy, but the spatial resolution, sensitivity, dynamic response, and bandwidth are insufficient leading to inaccurate flatness measurement
Solution Approach 1:
The roller body is segmented into multiple lamellas (thin plates) arranged axially, with each lamella equipped with optical fibre strain sensors. This segmentation allows independent measurement of strain at different axial positions, providing high spatial resolution along the roller axis while maintaining a relatively simple overall structure.
Solution Approach 2:
Conventional mechanical strain sensors are replaced with optical fibre strain sensors that use optical principles (light interference patterns) to measure strain. This substitution eliminates mechanical contact, reduces friction and wear, improves sensitivity and bandwidth, while the optical fibres can be integrated into the lamellas without significantly increasing structural complexity.
2Measurement precision
If conventional sensors are used in flatness rollers, then the device is simple to manufacture, but the sensitivity and dynamic response are insufficient for accurate flatness control
Solution Approach 1:
Optical fibre strain sensors are nested within the lamellas of the roller body. The fibres are embedded during manufacturing, with the lamellas and sensors integrated as a unified structure. This nesting approach protects the sensitive optical fibres while maintaining manufacturing simplicity through a streamlined production process.
Solution Approach 2:
The invention changes the measurement parameter from mechanical displacement (conventional sensors) to optical path length variations (optical fibres). This parameter change enables detection of extremely small strains through light interference patterns, dramatically improving sensitivity and dynamic response while the optical fibres maintain flexibility for integration into the roller structure.
3Measurement precision
If high sensitivity sensors are implemented in flatness rollers, then measurement accuracy improves, but maintenance costs and operational complexity increase
Solution Approach 1:
Mechanical strain sensors with moving parts, friction, and wear are replaced with optical fibre sensors that have no mechanical contact points. The optical fibres measure strain through light interference, eliminating wear, friction, and the need for mechanical calibration. This substitution maintains high measurement accuracy while dramatically reducing maintenance requirements and operational complexity.
Solution Approach 2:
The optical fibre strain sensors continuously monitor the strain state of the lamellas and provide real-time feedback without requiring external power or complex support systems. The sensors are passive elements that respond automatically to strain changes, eliminating the need for active components that would require maintenance. The system essentially monitors itself through the inherent optical properties of the fibres.
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 enhanced sensitivity and accuracy in strain measurement enable effective control of rolling operations, ensuring higher quality flatness in rolled sheets while reducing maintenance and operational costs.
Implementation Method 1
at least one optical fibre (54) comprising at least one strain sensor (22), each strain sensor (22) having a measurement axis
Implementation Method 2
each strain sensor (22) being arranged so that the angle between the corresponding measurement axis and a plane orthogonal to the axis of revolution X-X is less than or equal to 20°
Data Source
AI summary
A flatness roller includes a body having at least one cavity opening onto an outer surface of the body through a plurality of slots, two successive slots defining a lamella between them, each lamella being connected to the body by two connection portions. The flatness roller also includes at least one optical fibre having at least one strain sensor having a measurement axis. Each strain sensor is housed in a cavity and attached at a connection portion of a lamella, the measurement axis forming an angle less than or equal to 20° with a plane orthogonal to the axis of revolution of the body. Each strain sensor is configured to send an optical response wave representative of a strain of the strain sensor according to the measurement axis thereof.