Multi-Fractal Features of Fatigue Crack Surfaces in Relation to Crack Growth Rate

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Texture of a fatigue crack surface is strictly related to crack growth rate. Cracks in specimens from aluminum alloy were studied. Two types of information were used: SEM images of fracture surfaces, and 3D reconstructions of fracture surface morphologies. Sets of equidistantly focused images obtained by an optical microscope served as the basis for 3D reconstruction. Multiparametric fractal analysis was applied to characterize crack surfaces. A vector of fractal features represented each image or 3D reconstruction of selected locations of fracture surfaces. For estimating fractal characteristics, the box-counting method in 3D was used in all cases, [1]. Multilinear regression was used to express the relation between crack growth rate and feature vectors, with satisfactory results for both crack surface representations.

Info:

Periodical:

Materials Science Forum (Volumes 567-568)

Edited by:

Pavel Šandera

Pages:

129-132

Citation:

Z. Sekerešová and H. Lauschmann, "Multi-Fractal Features of Fatigue Crack Surfaces in Relation to Crack Growth Rate", Materials Science Forum, Vols. 567-568, pp. 129-132, 2008

Online since:

December 2007

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$38.00

[1] B.B. Mandelbrot: Fractal Geometry of Nature. Freeman, New York, 1982, 469 p.

[2] M. Ponec: The reconstruction of the morphology of crack surface from a set of blurred optical images. [Master's Thesis; in Czech] CTU Prague, 2005, 117p.

[3] Z. Sekerešová: Application of fractal geometry in textural fractography of fatigue fractures.

[4] H. O. Peitgen: Chaos and Fractals: New Frontiers of Science. Springer Verlag NY, Inc, 1992, 860 p.

[5] H, Lauschmann, M. Tůma, O. Ráček, I. Nedbal: Textural fractography. Image Analysis and Stereology, Vol. 21- Special issue (2002), S49-S59.

DOI: https://doi.org/10.5566/ias.v21.ps49-s59

[6] H. Lauschmann, Z. Sekerešová: Multiparametric fractal analysis with applications in fractography. In: Int. Conf. on Stereology, Spatial Statistics and Stochastic Geometry. Prague, Union of Czech Mathematicians and Physicists 2006, pp.281-286.

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15 INPUT: from the experiment OUTPUT: estimation from images Crack growth rate v [µm/cycle].

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5 INPUT: from the experiment OUTPUT: estimation from images Crack growth rate v [µm/cycle].