A finite element comparison between short and long cracks within a plastic zone due to a notch

Abstract This paper considers the finite element characteristics of a crack growing within an area affected by a small notch. It is a continuation of an investigation leading from the development of a finite element program which considers elastic-viscoplastic constitutive relations to the actual features present in modelling a crack growth within a specimen. A final paper actually compares given parameters developed within this paper with experimental findings. The material considered is IN 718 at a temperature of 1200°F. A compact tension with a blunt notch is the specimen eventually tested. The findings relate to the most effective technique for allowing the crack to grow within a specimen. A trace is carried out on stress and strain functions as the crack grows with a consideration of the closure phenomenon. Parameters such as the J range, COD, maximum stress and strain range, stress intensity, and effective stress intensity range are shown to be potential candidates for crack growth as short and long cracks are compared.

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