Author(s): A. Cormeau; M. Maes; I. J. Jordaan; G. Timco
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Keywords: No Keywords
Abstract: Recent experimental work by Timco and Frederking (OMAE, 1986) has shown that systems of microcracks introduced into ice specimens result in a reduction of the apparent stress intensity factor. This was interpreted to be associated with the enhancement of the stress field at the crack tip due to the presence of neighbouring cracks. The understanding of this process is important since ice in the field is characterized by systems of flaws. Because of the mutual interaction amongst the cracks, an analysis of failure in ice containing a number of cracks cannot be treated using a simple "single-flaw" fracture mechanics approach. To treat this problem, more complicated analyses have been proposed, mainly from related disciplines such as geophysics and metallurgy. These are implemented in a finite element analysis, which is used to complement other methods of analysis. The geometry of the test specimen in Timco and Frederking's tests is simulated by special elements and the microcracks with various densities are inserted into the matrix. The effect on the apparent critical stress intensity factor can thereby be investigated as a function of crack density. Comparisons between theory and experiment are given. The usefulness of a finite element approach for complicated LEFM in ice is demonstrated by the excellent agreement that is obtained between experimental and analytical results.
Year: 1986