Curve fitting of mixed-mode isopachics

R.I. Hebb, Janice .M. Barton, K. Worden, P. Tatum

Research output: Chapter in Book/Report/Conference proceedingConference Contribution (Conference Proceeding)


Recent work has focused on exploiting the observation that the stress-sum contours (isopachics), obtained from TSA, in the vicinity of the tip take the form of a simple curve ? the cardioid. The analysis made use of the cardioid nature of the isopachics by deriving expressions for the SIFs in terms of the cardioid area and the positions of certain tangents to the curve. Both Genetic Algorithms (GAs) and Differential Evolution (DE) have also proved successful for parameter estimation, but some of the curve-fits indicated that the cardioid form was inappropriate for the base model, particularly for mixed-mode cracks. The effect of cracktip interaction has been explored and shows this has a small effect on the cardioid form. New, higher resolution infra-red detectors have become available since the original data was collected, so the object of the current paper is to use new techniques to extract the cardioid form and use a GA to perform the curve fitting.
Original languageEnglish
Title of host publication7th International Conference on Modern Practice in Stress and Vibration Analysis
EditorsJ.M. Dulieu-Barton
PublisherInstitute of Physics
Number of pages1
Publication statusPublished - 1 Sept 2009


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