Optical Fiber Strain Sensor with Silicone Buffer
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Solution Overview
Problem
Conventional strain gauges are limited in measuring large strain ranges and are unsuitable for soft materials due to their rigid structure and reliance on electrical signals, which are not effective in environments with high temperatures and complex conditions such as the food and pulp & paper industries.
Innovation Solution
An optical fiber strain sensor with a reflective base and a glass tube, combined with a resilient buffer made of silicone, allowing for a large strain range measurement by modulating an optical signal indicative of strain, immune to electromagnetic interference and capable of withstanding high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional strain gauges are used for measuring strain, then electrical signals can be detected, but the measurement range is limited to small strain and they cannot measure large strain ranges
Solution Approach 1:
The patent replaces the conventional electrical signal-based strain gauge system with an optical fiber system. The optical fiber sensor uses light reflection and optical signal modulation to detect strain, eliminating the need for electrical signals and conductive materials. This substitution enables measurement of large strain ranges (up to 20% or more) and makes the sensor suitable for soft materials like foods and paper that cannot accommodate rigid electrical gauges.
Solution Approach 2:
The patent employs a flexible optical fiber as the sensing element, which can conform to soft and deformable surfaces. The optical fiber's flexibility allows it to be embedded in or attached to soft materials without damaging them, enabling strain measurement in applications like food processing and paper manufacturing where conventional rigid strain gauges would fail.
2Ease of manufacture
If conventional strain gauges are mounted on rigid surfaces, then electrical signals can be transmitted, but they require glue and surface polishing which complicates the manufacturing process
Solution Approach 1:
The optical fiber sensor eliminates the need for adhesive mounting and surface polishing by using a non-contact optical measurement approach. The fiber can be简单地 inserted or attached to the surface, and the optical reflection principle requires no surface preparation, significantly simplifying the manufacturing and installation process compared to conventional electrical strain gauges.
3Reliability
If electrical signal-based sensors are used, then strain can be measured, but they are affected by electromagnetic interference in complex environments
Solution Approach 1:
The patent replaces electrical signal transmission with optical signal transmission through the fiber optic sensor. Optical signals are immune to electromagnetic interference, making the sensor highly reliable in complex environments such as those with microwave radiation, high temperatures, and electromagnetic fields commonly found in food processing and paper manufacturing industries.
4Temperature
If conventional strain gauges are used for high temperature environments, then measurements can be taken, but the electrical components cannot withstand temperatures above 300°C
Solution Approach 1:
The optical fiber sensor replaces electrical components with optical components that can withstand high temperatures. The optical fiber and reflective base are constructed from materials suitable for high-temperature environments, allowing reliable strain measurement in processes like drying and heating where temperatures exceed 300°C, which would damage conventional electrical strain gauges.
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
Enables accurate strain measurement in soft materials with a large strain range, suitable for environments with high temperatures and complex conditions, overcoming the limitations of conventional strain gauges.
Implementation Method 1
a reflective base adapted to reflect a divergent optical signal
Implementation Method 2
The optic fiber has a proximate end and a distal end, such that the optical fiber is configured for transporting an optic signal indicative of the detected strain
Implementation Method 3
A resilient buffer is concentrically disposed around the optic fiber and the glass tube, such that the buffer adheres to the glass tube and also adheres to a portion of the optical fiber extending from the glass tube
Data Source
AI summary
A strain gauge device employs a reflective base adapted to reflect a divergent optical signal, and a glass tube attached to the reflective base for optical communication therewith, the glass tube having a working length into which an optical fiber is inserted. The optical fiber is configured for transporting an optic signal indicative of the detected strain. The optic fiber has an outside diameter slightly smaller than an inside diameter of the glass tube for providing a slight tolerance. A distal end is disposed in slidable communication with an interior of the glass tube and accommodated by the tolerance, and a sensing circuit at the proximate end receives an optical signal indicative of strain or displacement. A resilient buffer layer made of soft silicone is disposed outside the glass tube to allow for large deformation measurements and reduce the distortion of the deformation by the introduction of the sensor.