X-ray Diffraction Residual Stress Measurement Tilting
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Solution Overview
Problem
Current methods for determining residual mechanical stresses in objects, especially large and heavy ones, are cumbersome and require precise alignment and sample rotation, which can be impractical and error-prone.
Innovation Solution
A device using a source of X-rays or neutrons with a detection system capable of measuring diffraction peaks at multiple orientations without rotating the sample, featuring a surface detector with a through opening to allow a wide range of inclination angles, enabling simultaneous measurement of diffraction peaks at different angles without sample movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a standard 2D detector is used with the sample close to the detector, then the detector can intercept the incident beam, but the observable angle range is reduced
Solution Approach 1:
The patent introduces a third dimension by tilting the sample surface relative to the incident beam. Instead of only moving the detector in the plane perpendicular to the beam, the sample is inclined at an angle α to the beam direction, allowing the diffraction cones to be intercepted at different positions on the detector surface, thereby expanding the observable angular range without reducing detector area.
2Measurement precision
If the sample is precisely aligned with the central point of the goniometer, then measurement accuracy is improved, but the alignment process becomes complex and error-prone
Solution Approach 1:
The patent extracts the alignment requirement from the goniometer system by using a fixed detector position and instead focusing on aligning the sample surface normal with the incident beam direction. This simplifies the alignment process by eliminating the need for precise goniometer centering while maintaining measurement accuracy through the fixed geometry of the detector-sample-source arrangement.
3Adaptability or versatility
If the sample is rotated around the X axis to define a new range of measurable angles, then the observable angle range is expanded, but the rotation becomes difficult or impossible for large and heavy objects
Solution Approach 1:
Instead of rotating the sample to change the measurable angle range, the patent inverts the approach by keeping the sample fixed and using a tilted sample surface configuration. The incident beam is directed at an angle α to the sample surface normal, allowing the diffraction cones to be intercepted at different detector positions without requiring sample rotation, thus making the method applicable to large and heavy objects.
4Measurement precision
If multiple diffraction peaks are measured at different orientations, then the determination of residual stresses is improved, but the measurement time increases
Solution Approach 1:
The patent enables continuous measurement of multiple diffraction peaks by using a tilted sample surface that allows the diffraction cones corresponding to different peaks to be simultaneously intercepted on the detector. This continuous geometry eliminates the need for sequential sample rotations or repositioning, reducing measurement time while maintaining the ability to measure multiple peaks for accurate stress determination.
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 simplifies the process, eliminates the need for precise sample alignment and rotation, and allows for rapid acquisition of diffraction data, making it suitable for bulky and heavy objects while providing enhanced resolution and ease of use.
Implementation Method 1
device for determining the residual stresses in an object by diffraction
Implementation Method 2
comprising a source of X-rays or neutrons
Implementation Method 3
comprising a source of X-rays or neutrons
Implementation Method 4
Bragg's relation makes it possible to calculate the interreticular distance d hkl for a family of planes (hkl) in diffraction position
Data Source
Figure 1
Figure 2~3
AI summary
Device for determining residual stresses of at least one area of an object (E), comprising: - an X-ray source (S) emitting an incident beam along an incident direction (Z), - a surface detector (DD) for acquiring diffraction images, comprising an aperture aligned with the incident direction intercepting the diffracted beams for different values of the Bragg angle at different inclination angles ψ, allowing the acquisition of at least one diffraction image, - a specimen holder (P) supporting the object (E) such that the angle (ψ0) between the normal direction (N) to the surface of the object (E) and the incident direction (Z) is non-zero, the detection device (DD) being arranged with respect to the source (S) so that it is between the source (S) and the location intended for the object (E) and the active surface (2) is opposite the location intended for the object (E).