X-ray Diffractometry for Fiber Orientation Measurement
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Solution Overview
Problem
Existing methods for measuring the fiber orientation degree of carbon fibers in composite materials, such as X-ray computer tomography and microscopic observation, are time-consuming and expensive, and fail to accurately consider fiber orientation in the thickness direction.
Innovation Solution
A method using X-ray diffractometry to acquire diffraction images, calculate peak angles, correction coefficients, and diffraction sensitivity, and apply the Hermans method to determine the fiber orientation degree, accounting for fiber orientation in both the in-plane and thickness directions without the need for a standard control sample.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If X-ray computer tomography or microscopic observation is used to measure fiber orientation degree, then measurement information can be obtained, but the measurement process becomes time-consuming and expensive
Solution Approach 1:
The patent replaces mechanical observation methods (microscopic observation of polished surfaces) and complex imaging systems (X-ray CT) with X-ray diffractometry. This substitution uses diffraction patterns to directly obtain crystal orientation information, eliminating the need for time-consuming sample preparation and mechanical polishing while providing accurate fiber orientation degree measurement.
2Measurement precision
If conventional X-ray diffractometry is used to measure crystal orientation degree, then measurement can be performed, but the thickness direction fiber orientation cannot be considered
Solution Approach 1:
The patent extends the measurement from two-dimensional in-plane orientation to three-dimensional orientation by incorporating the thickness direction. This is achieved by measuring diffraction patterns at multiple azimuth angles and using the relationship between diffraction angle, azimuth angle, and fiber orientation to calculate orientation degree in the thickness direction, thereby recovering the third dimension of orientation information.
3Measurement precision
If a control sample with unidirectionally oriented carbon fibers is used to calculate fiber orientation degree, then crystal orientation can be determined, but the measurement process becomes complex and requires sample preparation
Solution Approach 1:
The patent extracts and removes the matrix resin influence from the diffraction pattern analysis. By separating the carbon fiber diffraction signal from the matrix resin background and using only the fiber orientation information, the method eliminates the need for control samples while directly calculating the fiber orientation degree from the sample's own diffraction data.
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 a more accurate and simplified measurement of fiber orientation degree in composite materials, reducing the need for expensive equipment and time-consuming sample preparation, and effectively considers fiber orientation in the thickness direction.
Implementation Method 1
a diffraction image acquisition process of irradiating a sample formed of a composite material containing discontinuous carbon fibers with an X-ray to acquire an X-ray diffraction image
Data Source
AI summary
Provided are a method for measuring a fiber orientation degree, a fiber orientation degree measurement apparatus, and a control program for a fiber orientation degree measurement apparatus considering fiber orientation in a thickness direction simply and accurately. The method for measuring a fiber orientation degree of the present invention includes a diffraction image acquisition process (Step S1) irradiating a sample with an X-ray to acquire an X-ray diffraction image, a peak angle calculation process (Step S2) calculating an angle (2θ)A of a peak originating from a crystal face of graphite of the X-ray diffraction image, a correction coefficient calculation process (Step S3) calculating a correction coefficient δ of a thickness of the sample, an upper limit calculation process (Step S4) calculating an upper limit (2θ)B of the peak of the crystal face of graphite, a diffraction sensitivity calculation process (Step S6) calculating a diffraction sensitivity Ic(φ) of the peak originating from the crystal face of graphite, and an orientation degree calculation process (Step S7) calculating a fiber orientation degree Sd(β) from the diffraction sensitivity Ic(φ).