Thermal Effect Standards for Composite Materials
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Solution Overview
Problem
Current methods for determining the thermal effect in resin-fiber composite materials are inadequate as they do not accurately account for the total thermal experience in terms of both time and temperature, leading to inaccurate assessments and potential misrepresentation of heat-induced degradation in composite materials.
Innovation Solution
A method involving the use of an oven with multiple temperature sensors to precisely control and monitor temperature, combined with the heat treatment of composite material specimens to create thermal effect standards, which are then used to calibrate infrared spectroscopy sensors and predict residual mechanical strength through multivariate calibration models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If oven temperature is monitored using standard calibration methods, then temperature readings can be obtained, but the readings may be off by 25 F due to not accounting for total thermal experience
Solution Approach 1:
The patent applies preliminary action by pre-heating the oven to the target temperature and maintaining it for a specified time period before introducing the composite standards. This ensures the oven reaches thermal equilibrium and the composite materials experience the complete thermal effect, including both temperature and time factors. The method systematically exposes standards to temperatures ranging from 250°F to 550°F for one hour each, creating a comprehensive thermal history that accurately represents the degradation conditions.
Solution Approach 2:
The patent implements feedback by using temperature sensors to continuously monitor the oven temperature during the heat treatment process. The system adjusts and maintains the oven temperature within the specified range based on real-time sensor readings, ensuring precise thermal exposure. This feedback mechanism allows for accurate control of the thermal experience, correcting deviations and ensuring consistent reproduction of thermal effects across all standards.
2Productivity
If the entire oven cavity area is used for calibration, then more standards can be processed, but the temperature distribution may not be uniform across all standards
Solution Approach 1:
The patent applies local quality by concentrating all composite standards in a specific localized area within the oven cavity rather than distributing them throughout the entire volume. This localized placement ensures that all standards experience uniform temperature conditions and thermal history, creating consistent thermal effects. The method specifies placing standards in a particular location where temperature distribution is known to be uniform, sacrificing some overall oven capacity to guarantee precision and reproducibility of thermal exposure for each standard.
3Ease of operation
If visual inspection is used to determine heat effect, then the process is simple and quick, but heat effect to composite materials may not be visually apparent
Solution Approach 1:
The patent replaces the mechanical/visual inspection system with an infrared spectroscopy-based detection system. Instead of relying on human visual inspection, the method uses infrared sensors to detect chemical changes in the composite materials caused by thermal exposure. The system captures infrared spectra at different wavelengths and uses multivariate calibration models to quantify the degree of heat effect, including resin decomposition, charring, and fiber degradation. This substitution enables detection of internal thermal damage that is not visible to the naked eye, significantly improving measurement precision while maintaining operational feasibility through automated spectral analysis.
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 allows for the accurate assessment of thermal effects in composite materials by accounting for both time and temperature, providing precise thermal standards that improve the calibration of infrared sensors and enhance the prediction of residual mechanical strength, thereby addressing the limitations of existing methods.
Implementation Method 1
monitoring the temperature output of the at least one temperature sensor
Implementation Method 2
heat treating the at least one composite material specimen as at least one thermal effect standard by operating the oven
Implementation Method 3
operating the oven according to the temperature output of the at least one temperature sensor
Implementation Method 4
irradiating the composite materials with broad-spectrum infrared energy, detecting infrared energy reflected from the composite material
Data Source
AI summary
A method for fabricating thermal effect standards includes providing an oven, placing at least one temperature sensor at measurement location in the oven, operating the oven, monitoring a temperature output of the at least one temperature sensor, providing at least one composite material specimen, placing the at least one composite material specimen at the measurement location in the oven and heat treating the at least one composite material specimen as at least one thermal effect standard by operating the oven according to the temperature output of the at least one temperature sensor. A method of determining a physical property of a composite material is also disclosed.