Change search
ReferencesLink to record
Permanent link

Direct link
Influence of surface roughness on thermography measurement
University West, Department of Engineering Science, Division of Automation Systems.
2014 (English)Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
Abstract [en]

This university Bachelor's Thesis was performed to explore the influence of surface roughness on the thermography measurement.

Thermography is a non-destructive testing method which can be used to detect cracks. However, it is hard to define how the surface roughness influences the emissivity and the result of a thermography measurement, as well as how the angle of the excitation source influences the result. Therefore, this work aims to define how the heating angle and surface roughness influence the thermography measurement, define the relationship between surface roughness and emissivity for the same crack, and define the influence of the angles which composed of the heating source, the direction of crack and the direction of surface roughness on thermography measurement.

In this report, the theories of radiation and Signal-to-noise ratio (SNR) were explained, clearly. Also, two kinds of experiments were set up. One is focus on how the heating angle influence the thermography measurement, the other is focus on how the angle of the heating source, in relation to the crack direction and the direction of surface roughness, influence the SNR value.

The conclusions of these experiments are that the heating of a crack increases as the angle decreases (from wide side to narrow side) and the angle ofincreases (from horizontal to vertical). Moreover, the SNR value decreases as the surface roughness increases. For the same surface roughness, the SNR value increases with increased crack angle (0°, 45° or 90°) and with decreased sample position angle (horizontal, 45°or vertical). What is more, the higher surface roughness, the larger the influence of the crack angle and the sample position angle. Finally, when the surface is polish, the crack angle and the sample position angle does not have any influence.

Place, publisher, year, edition, pages
2014. , 20 p.
Keyword [en]
Emissivity, Surface roughness, thermography measurement, crack direction, direction of surface roughness
National Category
URN: urn:nbn:se:hv:diva-6842Local ID: EXC580OAI: diva2:755581
Subject / course
Educational program
Available from: 2014-10-20 Created: 2014-10-15 Last updated: 2015-02-05Bibliographically approved

Open Access in DiVA

fulltext(1319 kB)271 downloads
File information
File name FULLTEXT01.pdfFile size 1319 kBChecksum SHA-512
Type fulltextMimetype application/pdf

By organisation
Division of Automation Systems

Search outside of DiVA

GoogleGoogle Scholar
Total: 271 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 272 hits
ReferencesLink to record
Permanent link

Direct link