Hyper-redundant Fiber Sensor Network for Composite Structural Health Monitoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Structural health monitoring systems in composite structures, such as aircraft, face challenges due to added weight and reduced structural integrity when conventional sensors like strain gauges are used, especially in harsh environments.
Innovation Solution
A hyper-redundant tactile sensor network integrated into composite structures using carbon or boron fiber sensor cells with a coaxial structure, where each cell has an inner fiber core acting as a strain gauge and a non-conductive outer layer, allowing for distributed stress measurement without compromising structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sensors (strain gauges, thermocouples) are permanently mounted in composite structures for structural health monitoring, then immediate feedback on in-use stresses and damage can be obtained, but the weight of the structure increases and structural integrity is weakened
Solution Approach 1:
The patent merges the sensing function with the structural fibers themselves. The fiber optic sensors are integrated directly into the composite structure during manufacturing, combining the structural reinforcement function with the sensing function. This eliminates the need for separate conventional sensors and their mounting infrastructure, thereby avoiding additional weight while maintaining structural integrity and enabling structural health monitoring.
Solution Approach 2:
The fiber optic elements serve multiple functions: they provide structural reinforcement as part of the composite material while simultaneously acting as sensors for stress and strain measurement. This multi-functionality resolves the contradiction by eliminating the need for separate sensing components that would add weight and compromise structural integrity.
2Reliability
If conventional sensors are permanently mounted in composite structures, then structural health monitoring is enabled, but the number and location of sensors are limited due to required infrastructure
Solution Approach 1:
The patent segments the sensing function into multiple distributed fiber optic elements embedded within the composite structure. Each fiber can independently sense stresses in its local region, enabling distributed monitoring throughout the structure. This segmentation allows sensors to be placed at any location during manufacturing without requiring post-manufacturing installation infrastructure, thereby greatly increasing adaptability and versatility.
Solution Approach 2:
The fiber optic sensors are incorporated into the composite structure during the manufacturing process itself, before the structure is put into service. This preliminary integration allows sensors to be placed in optimal locations for monitoring critical stress regions without requiring subsequent installation, thereby overcoming the infrastructure limitations that constrain conventional sensor placement.
3Reliability
If conventional sensors are used in harsh environments (extreme temperatures, shock, vibration, g-loading), then structural health monitoring is provided, but the system performance deteriorates
Solution Approach 1:
The fiber optic sensors are fully integrated into the composite matrix, experiencing the same environmental conditions and mechanical loads as the surrounding structural material. This homogeneous integration ensures that the sensors are equally protected by the composite structure and experience identical thermal, mechanical, and environmental conditions, thereby maintaining performance in harsh environments where conventional sensors would deteriorate.
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
This solution provides accurate, redundant, and distributed stress measurement within composite structures, enhancing structural integrity and enabling closed-loop control, particularly beneficial for aircraft and robotic arms by offering immediate feedback on stress levels and pressure distribution.
Implementation Method 1
Each of the fiber sensor cells has an inner fiber core and a non-conductive layer formed over the inner fiber core
Implementation Method 2
a non-conductive layer formed over the inner fiber core
Data Source
AI summary
A system and method are disclosed for measuring stress in a composite structure including an integral sensor network. The composite structure is formed in layers with each of the layers formed from parallel fibers. At least one of the layers includes a plurality of fiber sensor cells distributed among the parallel fibers. Each of the fiber sensor cells has an inner fiber core and a non-conductive layer formed over the inner fiber core. A controller is electrically coupled to each of the fiber sensor cells and configured to determine a level of stress in the composite structure based on a change in a resistance level of the inner fiber core of each of the fiber sensor cells. The fiber sensor cells may be in a single direction or may be in a weave pattern with a first group arranged at a non-zero angle with respect to a second group.