TY - JOUR

T1 - Low-coherence interferometry based roughness measurement on turbine blade surfaces using wavelet analysis

AU - Zou, Yibo

AU - Li, Yinan

AU - Kaestner, Markus

AU - Reithmeier, Eduard

N1 - Funding information: The authors would like to thank the “ German Research Foundation ” for funding the project “Multi Scale Geometry Measurement” within the Cooperate Research Centre SFB-871 “Product Regeneration”. At the same time, we are grateful for the support and cooperation of the doctoral program “Multifunctional Active and Reactive Interfaces and Surfaces (MARIO)” in Leibniz Universitaet Hannover.

PY - 2016/3/21

Y1 - 2016/3/21

N2 - In this paper, a non-contact optical system, a low-coherence interferometer (LCI), is introduced for the purpose of measuring the surface roughness of turbine blades. The designed system not only possesses a high vertical resolution and is able to acquire the roughness topography, but also it has a large vertical scanning range compared to other commonly used optical systems. The latter characteristic allows us to measure turbine blades surfaces with large curvature without collisions between the lens and the measurement object. After obtaining the surface topography, wavelet analysis is applied to decompose the original surface into multiple bandwidths to conduct a multiscale analysis. The results show that the developed LCI system proofs a good performance not only in obtaining the surface topography in the roughness scale but also in being able to measure surfaces of objects that possess a complex geometry in a large vertical range. Furthermore, the applied biorthogonal wavelet in this study has performed good amplitude and phase properties in extracting the roughness microstructures from the whole surface. Finally, the traditional roughness parameters, such as the mean surface roughness Sa and the Root Mean Square (RMS) roughness Sq, are evaluated in each decomposed subband and their correlations with the scale of each subband are analyzed.

AB - In this paper, a non-contact optical system, a low-coherence interferometer (LCI), is introduced for the purpose of measuring the surface roughness of turbine blades. The designed system not only possesses a high vertical resolution and is able to acquire the roughness topography, but also it has a large vertical scanning range compared to other commonly used optical systems. The latter characteristic allows us to measure turbine blades surfaces with large curvature without collisions between the lens and the measurement object. After obtaining the surface topography, wavelet analysis is applied to decompose the original surface into multiple bandwidths to conduct a multiscale analysis. The results show that the developed LCI system proofs a good performance not only in obtaining the surface topography in the roughness scale but also in being able to measure surfaces of objects that possess a complex geometry in a large vertical range. Furthermore, the applied biorthogonal wavelet in this study has performed good amplitude and phase properties in extracting the roughness microstructures from the whole surface. Finally, the traditional roughness parameters, such as the mean surface roughness Sa and the Root Mean Square (RMS) roughness Sq, are evaluated in each decomposed subband and their correlations with the scale of each subband are analyzed.

KW - Low-coherence interferometry

KW - Roughness measurement

KW - Wavelet analysis

UR - http://www.scopus.com/inward/record.url?scp=84959465854&partnerID=8YFLogxK

U2 - 10.1016/j.optlaseng.2016.02.011

DO - 10.1016/j.optlaseng.2016.02.011

M3 - Article

AN - SCOPUS:84959465854

VL - 82

SP - 113

EP - 121

JO - Optics and Lasers in Engineering

JF - Optics and Lasers in Engineering

SN - 0143-8166

ER -