Strain Sensing Cable Tie with Embedded FBG
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Solution Overview
Problem
Conventional strain sensors are difficult to install, prone to damage, and require electricity, making them unsuitable for widespread, cost-effective strain monitoring in structural and cable tie applications, particularly in elongated structures and old infrastructure, and there is a challenge in ensuring consistent pretension during cable tie installation.
Innovation Solution
Incorporating a fiber Bragg grating (FBG) or mechanical fuse into cable ties, which can be molded within the strap, providing a strain sensing mechanism that allows for continuous monitoring or indicating excessive strain, and featuring a visible indicator for mechanical fuse failure, enabling easy installation and remote monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional strain sensors are used for strain monitoring, then strain measurement capability is achieved, but installation difficulty increases and device complexity increases
Solution Approach 1:
The patent combines the strain sensing function with the cable tie structure by embedding an FBG sensor within the strap during the molding process. This integration eliminates the need for separate sensor installation, reducing installation complexity while maintaining strain measurement capability. The sensor becomes an intrinsic part of the cable tie rather than an add-on component.
Solution Approach 2:
The cable tie is designed to serve multiple functions: mechanical fastening and strain sensing. The FBG sensor embedded in the strap enables the cable tie to simultaneously perform its traditional securing function and provide strain monitoring, eliminating the need for separate sensing devices and reducing overall system complexity.
2Measurement precision
If conventional strain sensors are used for strain monitoring, then strain measurement capability is achieved, but device complexity and cost increase
Solution Approach 1:
The strain sensing function is merged with the cable tie structure through embedding an FBG sensor within the strap during molding. This integration reduces device complexity by eliminating separate sensor housings, mounting hardware, and associated components, while maintaining full strain measurement capability.
Solution Approach 2:
The patent employs a low-cost FBG sensor that can be molded directly into the cable tie, replacing expensive conventional strain sensors. The sensor is designed to be disposable or single-use, which reduces overall system cost and complexity while providing adequate strain monitoring for the application lifecycle.
3Measurement precision
If conventional strain sensors are used for strain monitoring, then strain measurement capability is achieved, but ease of manufacture decreases
Solution Approach 1:
The FBG sensor is embedded within the cable tie strap during the molding process, before final assembly. This preliminary integration of the sensor into the strap structure simplifies manufacturing by incorporating the sensing function during primary production rather than requiring post-manufacturing installation or complex assembly steps.
4Productivity
If cable ties are installed without pretension control, then installation speed increases, but reliability decreases due to inconsistent load distribution
Solution Approach 1:
The cable tie with embedded FBG sensor provides self-monitoring of strain and tension status. The sensor automatically detects and reports the tension state, enabling installers to quickly verify proper installation without complex tools or procedures. This self-service capability maintains high installation speed while ensuring reliable and consistent load distribution through real-time feedback.
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 embedded strain sensing cable ties facilitate modular, cost-effective, and damage-resistant monitoring of strain and fatigue, ensuring consistent pretension and easy inspection, with the ability to monitor strain over long distances without electrical interference.
Implementation Method 1
the strain sensing device is a fiber Bragg grating (FBG), which is preferably molded within the strap
Implementation Method 2
The mechanical fuse is preferably disposed on the strap and is made of a fuse material having a mechanical strength lower than a mechanical strength of the material of the strap so that the mechanical fuse will fracture or deform earlier than the material of the underlying strap when both the fuse and the strap experience the same increasing strain
Data Source
AI summary
A cable tie having a strain sensing device incorporated therein. In one embodiment, the strain sensing device is a fiber Bragg grating (FBG), which is preferably molded within the strap. In this case, the cable tie further includes a socket in optical communication with the fiber Bragg grating for coupling of the cable tie to an external light source. In another embodiment, the strain sensing device is a mechanical fuse that activates in the presence of a predetermined amount of strain on the cable tie. The mechanical fuse is preferably disposed on the strap and is made of a fuse material having a mechanical strength lower than a mechanical strength of the material of the strap so that the mechanical fuse will fracture or deform earlier than the material of the underlying strap when both the fuse and the strap experience the same increasing strain.