Abstract

Abstract : Local fractal dimensions alpha(Chi, Epsilon), which are closely related to crowding indices of individual islands and lakes formed by sectioning of fracture surfaces produced in Charpy impact testing of a high-strength and high-toughness steel (ASTM A723) alloy, have been determined by perimeter- yardstick analysis. In this type of analysis, the perimeter of an island or lake on a fracture surface section is measured at several different magnifications, and Richardson's equation is employed to determine the fractal dimension of the island or lake. Perimeter-yardstick analysis, which had not previously been applied to fracture surface analysis, yielded alpha(Chi, Epsilon),values ranging from 1.17 to 1.40 (mean: 1.28, standard deviation: 0.08) for Charpy fracture islands and lakes in ASTM A723 steel for epsilon-values near 0.00013 cm. The mean alpha(Chi, Epsilon)-value is consistent with the (global) fractal dimension of 1.25 obtained by slit-island analysis of the same fracture surface sections-- a value typical of high-strength steel alloys previously studied. The island-to- island and lake-to-lake variations of the local fractal dimensions reflect real variations analogous to differences in the fractal dimensions of the coastlines of Norway and England. Either the fracture surfaces are fractally inhomogeneous or the range of alpha(Chi, Epsilon)-values determines limits on the variation of the global multifractal dimensions D(q) and a(q). Fractals, Fracture, Crowding indices, Slit-Island Method.

Full Text

Published Version

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.