Strain Sensor With Detachable Connecting Member
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Solution Overview
Problem
Conventional strain sensors with optical fibers have limited measurable strain range due to the rigidity of the gage carrier, which restricts accurate measurement of low-rigidity objects and cannot handle large strains without stress concentration.
Innovation Solution
A strain sensor design featuring a first and second base with a detachable connecting member that applies tension to the optical fiber, allowing for independent base operation and reducing stress concentration, thereby expanding the measurable strain range and enabling accurate measurement of low-rigidity objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid gage carrier is used to support the optical fiber, then the sensor structure is stable and easy to manufacture, but the measurable strain range is limited and stress concentration occurs during large strain
Solution Approach 1:
The gage carrier is divided into multiple independent bases (first base and second base) that are detachably connected. This segmentation allows each base to independently follow the deformation of the measured object without stress concentration, while maintaining overall structural stability through the detachable connection.
Solution Approach 2:
The detachable connection between bases enables dynamic adaptation to different strain conditions. When large strain occurs, the connection can be detached to prevent stress concentration, and reattached when normal conditions resume, making the sensor adaptable to varying measurement requirements.
2Ease of manufacture
If a rigid gage carrier is used, then manufacturing is simplified, but accurate measurement of low-rigidity objects becomes difficult due to stress concentration
Solution Approach 1:
Dividing the gage carrier into multiple detachable bases simplifies manufacturing of each individual component while enabling accurate measurement of low-rigidity objects. Each base can be manufactured independently with standard processes, then assembled to create a flexible measurement system that doesn't concentrate stress on any single point.
Solution Approach 2:
The detachable connection acts as an intermediary between the rigid bases and the flexible optical fiber, allowing the system to accommodate low-rigidity objects without transmitting excessive stress, thereby maintaining measurement precision while keeping manufacturing simple.
3Reliability
If the optical fiber is fixed tightly to prevent movement, then measurement stability is improved, but stress concentration occurs during large strain exceeding the carrier's elastic limit
Solution Approach 1:
The optical fiber is fixed to multiple separate bases rather than a single continuous carrier. This segmentation distributes the stress across multiple fixation points, preventing stress concentration at any single point while maintaining measurement stability through the combined support of all bases.
Solution Approach 2:
The detachable connection between bases provides a cushioning mechanism that prevents stress concentration before it occurs. When large strain is detected, the connection can be detached in advance to protect the optical fiber from exceeding its elastic limit, thereby maintaining the strength and longevity of the sensor.
4Area of stationary object
If many strain sensors are arranged on a wide area to measure strain at multiple points, then measurement coverage is improved, but wiring complexity and electrical noise increase
Solution Approach 1:
The optical fiber serves multiple functions simultaneously: it acts as both the sensing element and the signal transmission medium. This multi-functionality eliminates the need for separate wiring for each sensor, reducing wiring complexity while maintaining wide-area measurement coverage through the flexibility of optical fiber deployment.
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 design widens the measurable strain range and ensures accurate strain measurement even on low-rigidity objects by preventing stress concentration and allowing free transmission of strain to the optical fiber.
Implementation Method 1
The strain sensor provided with an optical fiber has superior long-term reliability... so that signals can be transmitted over long distance
Implementation Method 2
obtains strain amount on the basis of changes of reflected light and scattering light which are transmitted through the optical fiber in response to deformations of the optical fiber
Data Source
Figure 1(a)~1(c)
Figure 2(a)~3
Figure 4(a)~5
AI summary
In a strain sensor and a method for installing a strain sensor according to the present invention, a first base fixes and supports one side of an optical fiber. A second base fixes and supports another side of the optical fiber. A connecting member is constituted of a separate member from the first base and the second base and is detachably mounted between the first base and the second base. Tension is applied to the optical fiber in a state in which the connecting member is mounted between the first base and the second base, and the optical fiber is fixed to and supported by the first base and the second base in a state in which tension is applied.