Thermal Diffusion Factor Measurement for Anisotropic Composites
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Solution Overview
Problem
Existing thermal diffusion factor measurement methods struggle with accuracy when dealing with anisotropic carbon fiber-reinforced composite materials, particularly those with significant thickness, as they are not designed to handle materials with varying thermal diffusion factors between the in-plane and thickness directions, and traditional methods using thermocouples are prone to measurement errors due to handling complexities and low accuracy in non-contact measurements.
Innovation Solution
A thermal diffusion factor measurement device and method utilizing a non-contact heating unit and temperature sensor, which calculates the thermal diffusion factor by integrating the phase delay of temperature cycles detected on the rear face of the sample, accounting for the intensity distribution of the detection sensitivity, allowing for accurate measurements in both the in-plane and thickness directions, even for thick samples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a thermocouple is used to measure sample temperature, then temperature detection can be achieved, but the fixation and removal of the thermocouple becomes complicated and measurement errors increase
Solution Approach 1:
The patent replaces the mechanical contact-based thermocouple measurement system with a non-contact optical measurement system using a radiation thermometer. This substitution eliminates the need for physical fixation of thermocouples to the sample surface, thereby removing the complexity of thermocouple installation and removal while maintaining temperature detection capability through optical radiation detection.
2Ease of operation
If a radiation thermometer is used for non-contact temperature measurement, then thermocouple handling complexity is reduced, but measurement accuracy decreases due to wide area detection
Solution Approach 1:
The patent applies local quality by making the detection region of the radiation thermometer coincide with the heating region through precise positioning. The measurement system is configured so that the thermometer detects temperature only from the specific local area where heating occurs, rather than averaging over a wide area. This localized detection approach maintains high measurement accuracy while preserving the non-contact operational convenience.
3Adaptability or versatility
If general thermal dissipation factor measurement methods are used, then isotropic materials can be measured, but accurate values cannot be obtained for anisotropic materials with thickness of 100 μm or more
Solution Approach 1:
The patent changes the measurement parameters by implementing periodic heating at specific frequencies and measuring the phase delay of temperature oscillations at the rear surface. This parameter change enables the differentiation between in-plane and thickness-direction thermal diffusion factors in anisotropic materials. By using AC calorimetry with phase detection rather than steady-state measurements, the system can accurately measure thermal properties in both directions for thick anisotropic samples.
4Measurement precision
If laser spot periodic heating is used with phase delay calculation, then thermal diffusion factor can be calculated, but accuracy declines when measuring thick anisotropic materials
Solution Approach 1:
The patent employs feedback by iteratively adjusting the thermal diffusion factor values in the heat conduction equation and comparing the calculated temperature distribution with actual measurement data. The measurement system uses phase delay information as feedback to refine the thermal property calculations. This feedback mechanism allows accurate determination of thermal diffusion factors in thick anisotropic materials by continuously optimizing the model parameters against experimental observations.
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 precise measurement of thermal diffusion factors in anisotropic materials with varying thickness, reducing measurement errors and improving accuracy by using non-contact detection and integral processing of temperature data, suitable for both tabular and rod-like samples.
Implementation Method 1
heating unit for periodically heating a heating location on a front face of an object to be measured in a non-contact manner
Implementation Method 2
non-contact temperature sensor for detecting the temperature of a detection location on the rear face of the object in a non-contact manner
Implementation Method 3
thermal diffusion factor computing unit for calculating a phase delay of a temperature cycle detected by the non-contact temperature sensor relative to a heating cycle generated by the heating unit, and computing a thermal diffusion factor of the object based on the calculated phase delay
Implementation Method 4
the thermal diffusion factor computing unit obtains an intensity of a detection sensitivity distribution at the detection location with respect to the temperature detected by the non-contact temperature sensor, subjects a phase of the detected temperature cycle at the detection location and the obtained intensity of the detection sensitivity distribution to integral processing, and thereby calculates a phase delay at the detection location
Data Source
AI summary
To provide a thermal diffusion factor measurement device, a thermal diffusion factor measurement method and a program capable of measuring thermal diffusion with high accuracy, even when an object to be measured has anisotropy in which thermal diffusion factors differ greatly between the in-plane direction and the thickness direction and a thick thickness. In a thermal diffusion factor measurement method, a heating location H on a tabular sample is made to generate periodically varying thermal waves and the thermal waves at a detection location S on the sample are detected by a non-contact temperature sensor. In addition, the phase delay of the thermal waves at the detection location S is detected in consideration of a detection sensitivity distribution DS of the non-contact temperature sensor and the thermal diffusion factor in the in-plane direction of the sample is measured using the phase delay.