A Qualitative Analysis of Crack Propagation in Articular Cartilage at Varying Rates of Tensile Loading
A custom-built miniature tensile testing apparatus was used to study the propagation of cracks through the articular cartilage matrix at various loading rates and initial crack lengths. The crack propagation mechanism was observed to be significantly dissimilar to that normally seen in traditional fracture mechanics opening mode, where fracture propagates through the thickness of samples or perpendicularly to the applied load. Instead, an artificially initiated microcrack in the surface layer of an articular cartilage sample grew laterally in the direction of the applied load, stretching about the crack tip, whose initial position remained unchanged throughout the fracture process. A progressive upward pull of the bottom layer toward the surface, which resulted in necking of the specimen, was observed. Our analysis revealed that the rate of necking was the same as that of the lateral stretch of the growing crack. We hypothesize that necking is due to the response of the collagen meshwork especially in the deep zones of the matrix to the tensile load. Our samples exhibited unstable fracture growth immediately after each microcrack grew to the base of the articular surface layer, with very fast crack propagation to failure, thereby indicating that the fracture toughness of the articular cartilage matrix is significantly determined by the toughness of its articular surface.
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|Item Type:||Journal Article|
|Additional Information:||For more information, please refer to the journal’s website (see hypertext link) or contact the author.|
|Keywords:||Articular Cartilage, Fracture Propagation, Cartilage Fracture Mechanism, Crack Growth, Surface Cracks, Tissue Matrix Damage|
|Divisions:||Past > QUT Faculties & Divisions > Faculty of Built Environment and Engineering|
|Copyright Owner:||Copyright 2003 Taylor & Francis|
|Copyright Statement:||First published in Connective Tissue Research 44(2):pp. 109-120.|
|Deposited On:||09 Oct 2007|
|Last Modified:||29 Feb 2012 23:00|
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