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Indexed by:期刊论文

Date of Publication:2012-12-01

Journal:INTERNATIONAL JOURNAL OF FATIGUE

Included Journals:SCIE

Volume:45

Page Number:1-7

ISSN No.:0142-1123

Key Words:Short fatigue cracks; Collective evolution; High temperature; Fractal dimension; Plastic strain energy density

Abstract:This paper proposes a Paris-type damage model to investigate the collective evolution of short fatigue cracks based on fractal theory. On the basis of experimentally determined images, the fractal dimensions (FDs) of rounded notched specimens' surfaces are numerically calculated by using Otsu threshold segmentation and box-counting dimension method. The results show that FDs' evolution presents "HILL" curves' characteristics. The transition period between FD rapid growth stage and FD constant stage takes place at about 30% of fatigue life. The good match between experimental results and FEM analyses reveals the model can describe collective damage process caused by all fatigue cracks. (C) 2012 Elsevier Ltd. All rights reserved.