Embedded Humidity Sensor for Composite Material Moisture Monitoring
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Solution Overview
Problem
Current methods for measuring humidity in composite materials, particularly in aeronautical applications, are inefficient and costly due to the need for extensive testing under wet and dry conditions, with no direct method available for in-service measurement of absorbed humidity, leading to weight and cost inefficiencies.
Innovation Solution
A system comprising a composite material with an embedded insert and ambient humidity sensor in a cavity, allowing for the measurement of internal humidity by correlating the humidity in the gas phase with the absorbed humidity in the composite material, enabling periodic checks and potential dehumidification interventions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional extensive testing under wet and dry conditions is performed for humidity measurement, then measurement reliability is improved, but loss of time and productivity deteriorate
Solution Approach 1:
The humidity sensor is embedded in the composite material during manufacturing, performing preliminary installation so that humidity measurement capability is built into the structure before service. This eliminates the need for subsequent extensive testing and allows direct in-service monitoring, resolving the contradiction between measurement reliability and testing time by establishing the measurement system in advance.
2Reliability
If traditional extensive testing under wet and dry conditions is performed for humidity measurement, then measurement reliability is improved, but productivity deteriorates
Solution Approach 1:
The patent replaces mechanical/testing-based humidity assessment with an electronic sensing system. The embedded humidity sensor provides direct electrical measurement of moisture content, substituting the need for time-consuming mechanical testing and certification processes. This resolves the contradiction by maintaining measurement reliability while dramatically improving certification productivity through automated sensor-based monitoring.
3Device complexity
If no direct measurement method is used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The humidity sensor is nested within the composite material structure itself, with the sensor positioned in a cavity or embedded between plies. This nesting approach allows the measurement system to be integrated into the existing structure without adding external complexity, while maintaining high measurement precision through direct contact with the composite material's humidity environment.
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 approach enables certification of composite structures under more favorable conditions, reducing material weight and production costs, and simplifying the certification process by allowing for 'dry' condition testing, thereby saving time and resources.
Implementation Method 1
an ambient humidity sensor positioned inside said cavity, and capable of providing a signal indicating the humidity content in the atmosphere present inside said cavity
Implementation Method 2
the rate at which saturation is reached in the different environments is controlled by the diffusion of the water within the polymer, and is thus a function of the diffusion coefficient
Data Source
AI summary
Systems are provided for measuring absorbed humidity in a composite material, including an item of composite material which includes a plurality of plies of material consolidated through the action of pressure and heat, wherein each ply of material is formed from a resin matrix reinforced with a fiber material, an insert embedded in the composite material, which is positioned in an interface zone between a first and a second ply of material, and in which at least one cavity is formed, in fluid communication with first and second ply of material, and an ambient humidity sensor positioned inside the cavity, capable of providing a signal indicating the humidity content in the atmosphere present inside the cavity. Corresponding methods are also provided.