scholarly journals Radiation Transmission-based Thickness Measurement Systems - Theory and Applications to Flat Rolled Strip Products

10.5772/8729 ◽  
2010 ◽  
Author(s):  
Mark E.
Keyword(s):  
Systems Theory ◽  
Thickness Measurement ◽  
Rolled Strip ◽  
Measurement Systems ◽  
Radiation Transmission

scholarly journals THE ACCURACY OF ULTRASONIC THICKNESS MEASUREMENT OF DISTORTED GRAIN STRUCTURE METAL SAMPLES

2017 ◽  
Vol 45 (4) ◽  
pp. 33
Author(s):  
Nada Nađ ◽  
Morana Mihaljević ◽  
Zdenka Keran ◽  
Amalija Horvatić–Novak
Keyword(s):  
Ultrasonic Velocity ◽  
Metal Forming ◽  
Thickness Measurement ◽  
Grain Structure ◽  
Measurement Systems ◽  
The Third ◽  
Specific Direction ◽  
Measurement Results ◽  
Ultrasonic Thickness Measurement ◽  
Ultrasonic Thickness

Thickness measurement is one of the commonly used control measurements in sheet metal forming. Ultrasonic thickness measurement systems demand access to the material only from one side which makes them very useful for this purpose. Distortion of grain structure of the workpiece influences ultrasonic velocity and in that way directly influences ultrasonic thickness measurement. Three different ultrasonic thickness measurement systems are examined on the same working sample. Two systems are defined by standard EN14127. The third system is not defined by the standard and includes previously measured ultrasonic velocity in specific direction of grain elongation. Statistical analysis shows relations between measurement results obtained by all three systems and highlights the third system as the most accurate one.

Thickness Measurement in the AEM by Macintosh-Based Analysis of Two-Beam Convergent Beam Patterns

1990 ◽  
Vol 48 (2) ◽  
pp. 504-505
Author(s):  
John F. Mansfield ◽  
Douglas C. Crawford
Keyword(s):  
Electron Microscope ◽  
Video Camera ◽  
Thickness Measurement ◽  
Specimen Thickness ◽  
Crystalline Materials ◽  
Beam Dynamic ◽  
Line Measurement ◽  
On Line ◽  
Image Position ◽  
Convergent Beam

A method has been developed that allows on-line measurement of the thickness of crystalline materials in the analytical electron microscope. Two-beam convergent beam electron diffraction (CBED) patterns are digitized from a JEOL 2000FX electron microscope into an Apple Macintosh II microcomputer via a Gatan #673 CCD Video Camera and an Imaging Systems Technology Video 1000 frame-capture board. It is necessary to know the lattice parameters of the sample since measurements are made of the spacing of the diffraction discs in order to calibrate the pattern. The sample thickness is calculated from measurements of the spacings of the fringes that are seen in the diffraction discs. This technique was pioneered by Kelly et al, who used the two-beam dynamic theory of MacGillavry relate the deviation parameter (Si) of the ith fringe from the exact Bragg condition to the specimen thickness (t) with the equation:Where ξg, is the extinction distance for that reflection and ni is an integer.

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